The introduction of mandatory gender quotas in party lists is a reform that many countries have recently adopted or have been considering. The electoral system affects the incumbents' incentives to make such reforms, their details, and their effectiveness. We show that male incumbents can actually expect an increased incumbency advantage when gender quotas are introduced, if they are elected through single-member district majority rule. On the other hand, no expectation of male advantage can reduce the incumbents' fear of being replaced if they are elected through closed-list proportional representation. As France has both electoral systems, we validate the above argument using a formal model of constitutional design as well as an empirical analysis of the legislative elections in France, displaying the existence of male bias in the last three elections. We also show that parity may have Assembly composition effects and policy effects that vary with the electoral system.