Over 43 million registered voters will be able to cast ballots to elect the remaining 501 members of the National Assembly, the lower chamber of parliament, for a five-year term.
Polling stations opened at 8 a.m. (0600GMT), with voting continuing for up to 12 hours, Anadolu Agency reported.
French President Emmanuel Macron dissolved the parliament and announced snap elections after the far-right National Rally (RN) swept more than 31% of the vote in the European Parliament elections on June 9, defeating his centrist bloc.
The first round of the elections took place on June 30 with a turnout of over 65% and over 49 million voters cast ballots.
The RN got 29.26% of the vote by itself, a rate that rises to over 33% when combined with its allies, according to official election results.
The left-wing alliance New Popular Front (NFP) got 28.06%, and the centrist Together for the Republic alliance backed by Macron finished third with slightly over 20.04%.
A political party or alliance needs at least 289 seats to secure a majority in the National Assembly.
Some candidates got a majority of at least 50% in their constituencies and were elected in the first round, hence a second round will not be held in 76 constituencies across France, where RN got 37 seats, NFP 32, and Together two.
However, candidates who fell short of 50% in the first round will now fight to have the highest tally.
More than 210 candidates - including 131 from the NFP and 82 from Together - who accessed the second round withdrew last week in favor of a stronger peer who might have a better chance of countering the far right.
SD/PR