This paper provides new evidence on how firms and workers adjust to a restriction on low-hour jobs. I exploit a unique reform introducing a minimum workweek of 24 hours in France in 2014 affecting 15% of jobs. Drawing on linked employer-employee data and an event study design, I find a firm-level reduction in the number of jobs and an increase in average hours per worker. Overall, total hours worked in the firm decreased significantly, showing imperfect substitutability between workers and hours. The effects differ by gender: part-time female workers were replaced by full-time male workers. Importantly, reduced-form evidence indicates the reallocation of workers from firms highly exposed to the policy to firms less exposed. To quantify the aggregate impact taking into account these effects, I build and estimate a search and matching model with heterogeneous workers and firms. I find that the minimum workweek destroyed 1% of jobs but no effect on total hours, due to positive general equilibrium effects. Finally, the gender gap in welfare increased by 3% because women were more affected by the direct negative employment effects and benefited less from reallocation effects.