We develop a structural model to investigate the effects of pharmaceutical price regulation on demand and on manufacturers’ price-setting behavior in France. We estimate price-cost margins in a regulated market with price constraints and infer whether these constraints are binding, exploiting cost restrictions across drugs, which come from observing the same drugs in potentially price-constrained markets (France) and in markets where prices are unregulated (United States and Germany). Our counterfactual simulations suggest that price constraints generated modest savings for anti-ulcer drugs in 2003–2013 (2 percent of total expenses), relative to a free pricing scenario, and shifted consumption from generic to branded drugs. (JEL C51, D24, I18, L13, L51, L65)