On January 12, 2026, CREST and the Department of Economics of Institut Polytechnique de Paris welcomed a large audience for its annual lecture devoted to the Nobel Prize in Economics, hosted at CREST-ENSAE Paris.
The event featured Philippe Aghion, one of the recipients of the 2025 Nobel Prize in Economics, together with Antonin Bergeaud, winner of the 2025 Best Young Economist Prize.
The lecture opened with remarks by Antonin Bergeaud, who offered a personal and insightful introduction to Philippe Aghion’s work. Using the language of Schumpeterian growth, he highlighted the breadth of Aghion’s research agenda and the remarkable influence it has had across fields, institutions, and generations of economists.
Philippe Aghion then took the floor for his lecture, The Economics of Creative Destruction. Returning to the foundations of the Aghion-Howitt model, he explained how long-run growth emerges from a steady process of innovation, in which new ideas and technologies continuously replace older ones. This framework, he argued, remains a powerful tool for understanding some of today’s most pressing economic questions.
Throughout the lecture, Aghion illustrated how the concept of creative destruction helps make sense of historical and contemporary challenges, from industrial take-off to periods of slow growth, as well as the difficulties faced by middle-income countries. A recurring theme was the role of competition: not only as a driver of innovation, but also as a condition for the diffusion of new technologies and the renewal of economic activity.
The discussion also addressed the tensions between innovation, market concentration, and inequality. Philippe Aghion stressed that innovation-led growth does not have to come at the expense of social cohesion, provided that the right policy framework is in place. In this respect, he argued that elements of the American and European models can be combined, rather than opposed, notably through education, labor market institutions, and competition policy.
In the final part of the lecture, Philippe Aghion turned to the economic implications of artificial intelligence. While acknoledging its considerable potential for productivity gains and new forms of job creation, he also emphasized the importance of competition and skills in ensuring that these benefits are broadly shared.
Conference replay
The full lecture is now available on the CREST YouTube channel.
DeFi Workshop 2025
On 15-16 December 2025, CREST-Institut Polytechnique de Paris and Grenoble INP jointly hosted the DeFi Workshop 2025 in Grenoble, France.
The workshop brought together researchers working on the economics, infrastructure, and design of blockchain and decentralized finance (DeFi).
The event was supported by the French National Research Agency (ANR) through its grant for the project Blockchain and Decentralized Finance (BLOCKFI).
Day 1: Markets, Incentives, and Protocol Design
The first day featured a series of talks on blockchain microstructure, market design, incentives, and governance. Paolo Guasoni (Dublin City University) analyzed the dynamics of Bitcoin mempool, finding key determinants of fees and waiting times during congestion. Nir Chemaya (Ben-Gurion University of the Negev) introduced Clever Look-ahead Volatility Reduction (CLVR), a transaction ordering rule for AMM-based exchanges, designed to reduce intra-block price volatility and improve execution outcomes.
Several presentations focused on staking and incentives. Fayçal Drissi (University of Oxford) discussed the macroeconomic implications of liquid staking, while Boyang Mu (IP Paris) presented a microeconomic model showing how reputation mechanisms can discipline operators in delegated staking and restaking protocols.
Market performance and mechanism design were explored by Lorenzo Schoenleber (Collegio Carlo Alberto), who provided evidence of systemic frictions in prediction markets. Michele Fabi (IP Paris) studied automated market-making mechanisms for peer-to-peer energy sharing, demonstrating substantial gains over grid-only benchmarks.
Julian Ma (Ethereum Foundation) discussed proposed improvements to Ethereum’s transaction sequencing and inclusion mechanisms (EIP-7805) aimed at improving user experience and limiting transaction reordering manipulation.
The day was concluded by three presentations: Mnacho Echenim (Grenoble INP) presented work on formally verifying optimal trade splitting across concentrated liquidity pools using Isabelle/HOL. Aklis Georgiadis-Harris (University of Warwick) challenged the view of banks as inherently fragile through a mechanism-design framework yielding efficient equilibria without bank runs. Yiyun Zheng (IP Paris) presented her analysis of how airdrop design shapes platform growth and governance.
Day 2: Risk, Scaling; and Network Perspectives
The second day opened with Maarten van Oordt (Vrije University Amsterdam), who examined rational cryptocurrency bubbles driven by expected investment inflows. Following this, Louis Latournerie (IP Paris) presented his mathematical model of the Aave lending protocol, which incorporates liquidation strategies to quantify protocol-level risk.
Roman Kozhan (Warwick Business School) showed that informed liquidity provision on decentralized exchanges, particularly near-current-price activity in low-fee pools, plays a significant role in price discovery. Further insights were provided by Emmanuel Gobet (Sorbonne University), who demonstrated in an optimal stopping model for Uniswap v3 that liquidity providers should optimally concentrate liquidity in a single range.
Daniel Augot (Inria, IP Paris) explained the cryptographic foundations of zero-knowledge proofs to enhance Ethereum’s scalability, highlighting STARK-based proof systems. Yackolley Amoussou-Guenou (Panthéon-Assas University) highlighted persistent censorship risks in Proof-of-Stake systems due to weak validator incentives for enforcing fair transaction ordering.
The workshop concluded with two talks on applying network analysis to assess decentralized ecosystems. Natkamon Tovanich (TU Wien) presented network-based frameworks for uncovering money flows, user behaviors, and economic activities on blockchains. Emphasizing the importance of real-time DeFi monitoring and risk analysis, Julien Prat (IP Paris) demonstrated that network topology plays a crucial role in contagion within the DeFi lending protocol.
The DeFi Workshop 2025 showcased the breadth and depth of current research in blockchain and decentralized ecosystems, fostering cross-disciplinary dialogue and setting the stage for future collaborations across economics, computer science, and cryptography.
Le déclin démographique en France : une urgence économique et sociale
2025 : le solde naturel de la France devient négatif pour la première fois depuis 1945
Selon les chiffres de l’Insee publiés le 13 janvier 2026, 2025 marque une rupture historique : pour la première fois depuis la fin de la Seconde Guerre mondiale, le solde naturel de la France est négatif. L’année dernière, le pays a enregistré plus de décès (651 000) que de naissances (645 000), soit un solde de -6 000. Parallèlement, l’indicateur conjoncturel de fécondité (ICF) atteint un niveau historiquement bas, avec 1,56 enfant par femme, le plus faible depuis 1917.
Faut-il s’en inquiéter ? Dans son livre Le déclin démographique : une urgence économique (PUF, 2026), Pauline Rossi, économiste, chercheuse au CREST et Professeure à l’École polytechnique, propose une analyse approfondie des origines et des conséquences de ce phénomène. Ses travaux, menés au sein du CREST, montrent que la baisse de la natalité et le vieillissement de la population s’inscrivent dans un mouvement global vers plus de prospérité économique et de liberté individuelle. Comme les transitions énergétiques et technologiques, la transition démographique exige de repenser notre organisation économique et sociale pour garantir un progrès plus durable et inclusif.
Un phénomène mondial et structurel
Le déclin démographique n’est pas spécifique à la France. Comme le souligne Pauline Rossi, il s’agit d’un phénomène mondial, comparable par son ampleur et ses défis à la transition climatique. Dans le cadre de son projet ERC P3OPLE (Peers and Possible Partners: exploring the Origins of Population Long-term Equilibria), elle étudie notamment comment les politiques publiques peuvent influencer les dynamiques démographiques et réduire les inégalités, en particulier celles liées à la parentalité et à la conciliation entre vie professionnelle et vie familiale.
Ses recherches montrent que les politiques natalistes traditionnelles ont souvent des effets limités. Elle plaide pour une reconnaissance du travail parental comme un investissement collectif, et pour une refonte des politiques publiques afin de mieux soutenir les familles et favoriser l’égalité entre les sexes.
Quelles conséquences pour l’économie et la société ?
Le vieillissement de la population et la baisse de la natalité posent des défis majeurs : financement des retraites, pression sur les systèmes de santé, pénurie de main-d’oeuvre dans certains secteurs, et adaptation des infrastructures. La France, avec une espérance de vie parmi les plus élevées d’Europe, doit anticiper ces transformations pour en faire une opportunité de développement durable et inclusif.
Pauline Rossi insiste sur la nécessité d’une transition démographique maîtrisée, qui passe par l’innovation sociale, la valorisation du capital humain et une meilleure répartition des ressources. Ses travaux dans le cadre de son ERC P3OPLE visent à identifier les leviers politiques les plus efficaces pour accompagner cette transition, en s’appuyant sur des données rigoureuses et des analyses comparatives internationales.
Pour aller plus loin
La presse en parle
- Bilan démographique 2025 : légère hausse de la population malgré un solde naturel négatif, Vie publique, janvier 2026.
- Pauline Rossi, économiste : « La découverte du déclin démographique ressemble à celle du changement climatique », Le Figaro, avril 2025.
- Les raisons profondes du déclin de la natalité sont là pour durer, Les Échos, janvier 2026.
- Chute de la natalité : il faut s’adapter, même la Chine n’arrive pas à la faire remonter, Le Progrès, janvier 2026.
- Quelles sont les conséquences économiques du déclin démographique ?, France Culture, janvier 2026
- Baisse de la natalité : “Il y a une vraie tension entre les besoins du collectif et les choix individuels”, Libération, janvier 2026
- Il y a eu plus de décès que de naissances en France en 2025 : pourquoi ce “ce solde négatif” bouscule les équilibres économiques et sociaux, Le Nouvel Obs, janvier 2026
- Comment relever le choc démographique ?, BFM TV, janvier 2026
2nd CREST – IFAU Workshop on Labor Economics | Call for papers
Hommage à Roger Guesnerie
2025 CREST Highlights
As 2025 draws to a close, CREST reflects on a year marked by outstanding research achievements, prestigious recognitions, and impactful initiatives. Below is an overview of the laboratory’s key highlights.
This year was notably marked by CREST’s evaluation by HCERES, which recognised the laboratory as an excellent multidisciplinary research centre, particularly for the quality of its publications and its strong international visibility.
In 2025, CREST also organised its first retreat, a collective event dedicated to reflecting on the future of the laboratory and initiating concrete measures to improve laboratory life, internal communication, and the consideration of key issues such as research organisation, environmental policy, and international inclusion.
Key figures
- Researchers | 112
- PhD candidates | 100 PhD currently enrolled at CREST-Institut Polytechnique de Paris
- ERC Grants | 9 ERC grants in Economics, Sociology, and Statistics
Doctoral training
In 2025, CREST organised a series of doctoral courses delivered by professors from leading universities (MIT, Oxford, University of Tokyo, among others), offering advanced training to ENSAE Paris students and, in particular, to CREST PhD candidates. These courses enabled doctoral researchers to deepen their theoretical and methodological skills while engaging with cutting-edge research developed in academic environments beyond CREST.
20 PhD candidates graduated from CREST-IP Paris in 2025, pursuing a wide range of high-level career paths across academia, the public sector, and industry. Several alumni secured academic positions as Assistant Professors at institutions such as LMU Munich, ETH Zurich, and Hitotsubashi University. Other joined key public institutions, including a position as Head of the Families Study Section at INSEE, or transitioned to the private sector as Applied Scientist at Amazon and Economist at Malt. These placements reflect CREST’s strong commitment to doctoral training and its ability to prepare PhD graduates for impactful careers across sectors.
Research Breakthroughs: 204 Publications
In 2025, CREST published 204 scientific contributions, including conference papers presented at major international venues. Nearly 80% of these publications appeared in top Q1 journals, reflecting the breadth and depth of research conducted across the laboratory’s clusters.
Selected highlights include:
The Negligible Effect of Free Contraception on Fertility: Experimental Evidence from Burkina Faso, Pascaline Dupas, Seema Jayachandran, Adriana Lleras-Muney, Pauline Rossi, American Economic Review
From Public Labs to Private Firms: Magnitude and Channels of Local R&D Spillovers, Antonin Bergeaud, Arthur Guillouzouic, Emeric Henry, Clément Malgouyres, Quarterly Journal of Economics
The Biodiversity Premium, Guillaume Coqueret, Thomas Giroux, Olivier-David Zerbib, Ecological Economics
Propagation of a Carbon Price in a Credit Portfolio through Macroeconomic Factors, Géraldine Bouveret, Jean-François Chassagneux, Smail Ibbou, Antoine J. Jacquier, Lionel Sopgoui, SIAM Journal on Financial Mathematics
Machine Bias: How Do Generative Language Models Answer Opinion Polls?, Julien Boelaert, Samuel Coavoux, Etienne Ollion, Ivaylo Petev, Patrick Präg, Sociological Methods & Research
Beyond Indices: Profiles of Social Vulnerability Gap in Disaster Risk Perception, Eric Tate, Samuel Rufat, Md Asif Rahman, Shelley Hoover, International Journal of Disaster Risk Reduction
Mapping Cells trough Time and Space with MOSCOT, Dominik Klein et al., Nature
Asymptotic Equivalence of Locally Stationary Processes and Bivariate Gaussian White Noise, Cristina Butucea, Alexander Meister, Angelika Rohde, Annals of Statistics
Discover more CREST publications on our HAL webpage.
Impactful Events and Conferences
Throughout the year, CREST actively participated in and hosted events fostering collaboration and scientific exchange, including:
- Exploring Political and Economic Dynamics: A Conference with Guido Tabellini
- Summer School on Environmental Data Collection and Analysis for the Social Sciences
- Conference on Neural Information Processing Systems (NeurIPS) and CREST’s 19 accepted papers
- Navigating the Future of Money: The Futures of Money Workshop
- Paola Tubaro at Buenos Aires’ “Nuit des Idées” on the Invisible Workforce Behind AI
- Summer Institute in Computational Social Sciences with a focus on large language models and generative AI
Join future events: visit our calendar
Chairs and Research Structures
In 2025, CREST welcomed two new chairs:
- CARE | Assurabilité des Risques Emergents, led by Olivier Lopez, focusing on climate risk modelling, risk coverage and distribution mechanisms, and prevention strategies, with Allianz IARD, Institut Louis Bachelier, Fondation du Risque. More information here.
- Hi! Paris Chair, led by Etienne Ollion, developing the Textual Politics, project on the transformation of political analysis through natural language processing. More information here.
Awards and Recognitions
CREST researchers received numerous distinctions in 2025, including:
- ERC Advanced Grant awarded to Arnak Dalalyan for Statistical Analysis of Generative Models: Sampling Guarantees and Robustness (SAGMOS)
- ERC Starting Grant awarded to Anna Korba for Efficient Infinite-Dimensional Optimization over Measures (OptInfinite)
- Etienne Ollion, honourable mention by the American Political Science Associate for his book The Candidates
- Maddalena Conte, recipient of the Philippe Martin Best Thesis Award in Economics for her work on highlighting the decisive role of professional networks, access to housing, and business location in regional inequalities.
- Thomas Giroux, recipient of the 2025 Award for Young Researchers in Green Finance from the Banque de France.
Several CREST researchers were also appointed to key institutional roles, including the Conseil d’Analyse Economique, for Emmanuelle Taugourdeau and Pauline Rossi, Patricia Crifo was named a Senior Advisor at la Cour des Comptes. Julien Prat was named Head of the Department of Economics-Sociology at Institut Polytechnique de Paris.
Books, Projects, and Initiatives
In 2025, CREST researchers authored and contributed to major collective works and projects:
- Handbook of Quantitative Finance, edited by Peter Tankov and Ruixing Zhang, addressing sustainability, climate risk, regulation, and sustainable financial instruments.
- Google has again supported CREST researchers:
- Anna Korba for her project “Optimizing Diffusion Models via Generative Bilevel Learning“
- Vianney Perchet for his project “Design, Incentivization, Optimization and (Reinforcement-)Learning of Multi-Layered Market“
- Guillaume Hollard launched OrienteExpress, a research project with Ecole polytechnique and Docaposte (Index Education) on AI for career guidance and equal opportunities.
- Observatory of Equal Opportunities, jointly launched by IP Paris, the Ecoles Normales Supérieures, and the Institut des Politiques Publiques, with CREST researchers contributing to the analysis of inequalities in access to elite higher education.
This year also marked the third season of the Beyond the PhD video series, featuring Benoît Schmutz-Bloch, Caroline Hillairet, Paola Tubaro, and Nicolas Chopin, who shared their thoughts on the PhD journey, its impact on their careers, and the broader role of research in society.
Media and Outreach
In 2025, CREST researchers were featured in:
- More than 100 media outlets, including, Le Monde, Les Echos, France Culture, Libération, and La Tribune.
- 24+ op-eds and expert articles contributing to public debate.
Featured interview: Béatrice Cherrier discusses the 2025 Nobel Prize in Economics. Listen here.
International Scientific Exchange
In 2025, CREST organised 228 research seminars across macroeconomics, applied microeconomics, sociology, finance and financial econometrics, quantitative sustainable economics and finance, statistics, actuarial science, mathematical finance, and AI for social sciences. Researchers from 20 countries were invited, representing institutions across North America, Europe, and Asia, including UCLA, MIT, Yale, Columbia, Northwestern, Oxford, LSE, ETH Zurich, Bocconi, HEC Lausanne, KU Leuven, LMU, Toronto, Waseda, and Osaka University. This extensive programme further reinforced CREST’s role as a central hub for international research dialogue.
CREST celebrated a year of remarkable achievements and meaningful contributions to research, society, and global debates. From groundbreaking publications to prestigious awards and high-level scientific exchanges, CREST community continues to push boundaries and foster innovation.
Looking ahead, CREST remains committed to advancing interdisciplinary research, addressing major societal challenges, and nurturing a collaborative and inclusive environment for researchers and students alike.
Dépendances commerciales européennes : une recherche du CREST identifie 49 produits critiques
À l’heure où les chaînes de valeur mondiales sont soumises à des tensions accrues, comprendre les dépendances commerciales de l’Union européenne est devenu un enjeu central pour la politique économique.
Dans un article de recherche coécrit avec Isabelle Méjean, Pierre Rousseaux, doctorant au CREST-Groupe ENSAE-ENSAI, propose une méthodologie originale pour identifier les dépendances commerciales qui exposent l’UE à des risques élevés de rupture d’approvisionnement.
Une approche affinée des dépendances commerciales
À partir de données très détaillées sur le commerce international, les auteurs vont au-delà des approches classiques fondées uniquement sur la concentration des importations. Leur analyse intègre trois dimensions essentielles :
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les capacités de production au sein de l’Union européenne,
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les possibilités de substitution après un choc d’approvisionnement,
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la rigidité des relations commerciales entre partenaires (stickiness).
Cette approche permet de distinguer les dépendances apparentes de celles qui sont réellement problématiques en cas de crise.
49 produits au cœur des fragilités européennes
En combinant ces critères, la recherche montre que, parmi plusieurs centaines de produits initialement considérés comme sensibles, 49 produits concentrent une dépendance commerciale particulièrement critique pour l’Union européenne.
Ces produits se situent majoritairement en amont des chaînes de valeur, notamment dans les secteurs de la chimie, de l’énergie et des matériaux. Leur rôle stratégique implique qu’une perturbation de leur approvisionnement pourrait avoir des effets en cascade sur de nombreux secteurs industriels européens.
Une recherche présentée au grand public sur France Culture
Ces résultats ont été présentés et discutés dans l’émission Les Chantiers de la recherche sur France Culture, offrant une mise en perspective pédagogique des enjeux liés aux dépendances commerciales européennes et à la résilience des chaînes de valeur.
L’article académique développe plus largement la hiérarchisation des risques — géopolitiques, industriels, sanitaires et liés aux technologies vertes — ainsi que les implications pour la conception des politiques publiques européennes en matière de résilience économique.
👉 Accéder au papier de recherche
👉 Écouter l’émission sur France Culture
Nous remercions Pierre Rousseaux pour la clarté de ses éclaircissements et sa contribution à la diffusion de ces travaux auprès d’un large public.
Thomas Giroux lauréat du Prix du meilleur jeune chercheur en finance verte de la Banque de France
Thomas Giroux, ancien doctorant du CREST ayant récemment soutenu sa thèse “Walking the talk of impact investing”, a reçu le Prix du meilleur jeune chercheur en finance verte 2025 décerné par la Banque de France, le 17 décembre 2025, à l’occasion de la conférence Green Finance Research Advances (GFRA).
Cette distinction prestigieuse récompense des travaux de recherche de très haut niveau contribuant à l’analyse des enjeux financiers liés à la transition environnementale. Elle vient couronner un parcours académique remarquable : Thomas Giroux a récemment été recruté en tant qu’Assistant Professor à l’ETH Zurich, l’une des institutions les plus réputées au niveau international.
Ce prix revêt également une dimension symbolique forte pour le CREST. En effet, Olivier-David Zerbib, chercheur au CREST et Professeur à l’ENSAE Paris, avait lui-même reçu ce prix en 2020. Avec cette nouvelle distinction, le CREST compte désormais deux lauréats de ce prix, confirmant son positionnement de premier plan dans le champ de la finance environnementale et de la finance verte.
Le CREST adresse ses chaleureuses félicitations à Thomas Giroux pour cette reconnaissance majeure et se réjouit de voir ses anciens doctorants contribuer activement aux avancées de la recherche internationale sur les enjeux climatiques et financiers.
👉 Plus d’informations sur le Prix Jeunes Chercheurs en finance verte de la Banque de France
New Book Publication | Peter Tankov
Peter Tankov, researcher at CREST and Professor of Quantitative Finance at ENSAE Paris and Institut Polytechnique de Paris, has just published a new book, co-edited with Ruixun Zhang (Peking University), Handbook of Quantitative Sustainable Finance, this book is included in the Chapman and Hall / CRC Financial Mathematics Series.
The handbook brings together contributions from leading researchers working at the crossroads of quantitative finance and sustainability. It explores a wide range of topics, including climate and transition risks, sustainable asset pricing, portfolio management, regulation, data and measurement, and the design of sustainable financial instruments. The volume aims to provide both a rigorous and accessible reference for researchers, practitioners, and policymakers interested in sustainable finance.
This book naturally builds on Peter Tankov’s recent work in the field. In 2025, his research has examined the role investors can play in curbing greenwasghing (Journal of Economic Dynamics and Control) and proposed quantitative models to assess how climate transition uncertainty affects corporate debt valuation (Mathematical Finance). Together, these contributions highlight his ongoing engagement with the quantitative challenges raised by the transition to a low-carbon economy.
About the author
Peter Tankov is a senior researcher at CREST and a Professor of Quantitative Finance at ENSAE Paris. His research focuses on mathematical finance, with particular interests in asset pricing, energy and commodity markets, and climate-related financial risks. He has published extensively in leading academic journals and is actively involved in developing quantitative tools to better understand the financial implications of climate change and the transition to a low-carbon economy.
More information about the book is available on the publisher’s website: https://www.routledge.com/Handbook-of-Quantitative-Sustainable-Finance/Tankov-Zhang/p/book/9781032627922
Benoît Schmutz-Bloch, l’économiste qui ausculte la ville et ses dynamiques sociales
