Jean-Luc Mélenchon, leader of France Unbowed (LFI), tells supporters he is "so immensely relieved" as exit polls indicate a lead for his left-wing New Popular Front alliance.
Many had expected the far-right National Rally (RN) to win a majority of seats in parliament, after a strong performance in the election's first round.
Mélenchon went on to thank the French people for their "obstinate patience".