The French parliament is composed of the National Assembly (Assemblée Nationale) and the Senate (Sénat). The National Assembly is elected every five years, the same year as the presidential elections.

There are 577 seats in the National Assembly. The deputés (MPs) are elected in single-member constituencies in a two-round vote, just like the French president.

All candidates who receive at least 12,5% of the electorate (which includes all registered voters, whether they cast a vote or not) go into the runoff, unless one candidate gets the absolute majority of valid votes (=votes that were actually cast) and 25% of the electorate (=all registered voters), in which case this candidate wins the seat and there is no runoff.
In the runoff, which is held one week after the first round, the candidate with the most votes is elected.