In this paper, we analyze the impact of short-time work programs on the French labor market during the COVID-19 pandemic. We develop a dynamic model with incomplete markets, search frictions, human capital, and aggregate and idiosyncratic productivity shocks. We calibrate our model and simulate what the labor market response to a lockdown shock would have been under various STW programs. We show that STW succeeded in stabilizing employment and consumption but generated substantial windfall effects characterized by an excessive reduction in hours worked.