We exploit the unique features of the promotion system for French academics to examine the causes of the promotion gap between men and women. Promotions occur through national competitions for which we have information on candidates and on those eligible to be candidates. We find that gender has no significant effect on candidates promotion rates. In contrast, women have a lower probability to be candidates, which is not driven by differences in the objective costs or rewards of the contest. A possible interpretation of our results is that women are less willing than men to participate in contests, in line with recent experimental evidence.