Do female and male candidates campaign differently, and why? Using individual political platforms from French legislative elections between 1981 and 2024, I combine computational text analysis with a regression discontinuity design that exploits the two-round structure of French elections to identify the causal impact of candidate gender on campaign content. Between the first and second rounds, female candidates increase the salience of security and foreign policy by 9.2 percentage points relative to male candidates, while differences in other topics are negligible. This strategic shift is concentrated in districts that have never elected a woman or where the gender wage gap is above the median, consistent with women anticipating voter bias. I show that women only adapt to the gender of their opponent in districts where the voters are more biased against women, and that once elected, gender differences disappear.