The ballots provide a crucial coda to April's presidential election when Emmanuel Macron won a second term and pledged a transformative new era:
Elections for the 577 seats in the lower house National Assembly are a two-round process, with the shape of the new parliament becoming clear only after the second round on 19 JuneFrance began voting in the first round of parliamentary elections on Sunday, with a resurgent and newly unified left seeking to thwart President Emmanuel Macron's plans for reform.
Opinion polls show the president's centrist alliance, Ensemble , and Melenchon's NUPES coalition of hard left, Socialists, Communists and Greens neck-and-neck in the popular vote. It would raise the spectre of a clunky "cohabitation" — where the prime minister and president hail from different factions — which has paralysed French politics in the past.
Polls have indicated that Mr Macron's alliance is expected to win the largest number of seats but is by no means assured of getting over the line of 289 for an absolute majority.