Laws enforcing female quotas to correct for gender imbalance in leading positions are becoming more popular. We experimentally study the short-term effect of such quotas. Between treatments, we vary whether the affirmed group is discriminated against or not. When quotas are introduced in settings without discrimination, we observe a decrease in the performance of the affirmed individuals. We also observe an increase in sabotage and a reduction in help received by affirmed types. When affirmed individuals are discriminated against, we do not observe these negative effects. Our findings suggest that perceived justification crucially determines the success of a quota intervention.