A man casts his vote in the first round of parliamentary elections in Le Touquet, northwestern France, on Sunday. AFP

French people voted on Sunday in the first round of high-stakes snap parliamentary elections which could see the far-right party of Marine Le Pen take power in a historic first.

With Russia's war against Ukraine in its third year and energy and food prices much higher, support for the anti-immigration and eurosceptic National Rally (RN) party has surged despite President Emmanuel Macron's pledges to prevent its ascent.

The vote could put the far-right in power in France for the first time since the Nazi occupation in World War II.

Polling stations opened across mainland France at 8:00 am (0600 GMT) and will close 12 hours later, immediately followed by projections that usually predict the result with a degree of accuracy.

Voters in France's overseas territories that span the globe cast ballots earlier in the weekend. Some 49 million people are eligible to vote.

"These are not easy elections, the results are very uncertain, and the repercussions could be serious for society", said Julien Martin, a 38-year-old architect in the southwestern city of Bordeaux.

Candidate for upcoming legislative elections Manuel Bompard arrives at a polling station in Marseille on Sunday. AFP

Voters lined up to cast their ballots in France's Pacific territory of New Caledonia, where tensions remain high following last month's deadly riots.

The vote is "decisive", said Cassandre Cazaux, a nurse.

"It should be well attended, but I don't know if everyone will play along and come out to vote," Cazaux added.

By midday local time, turnout in the archipelago, which is located between Australia and Fiji, stood at 32.4 percent, compared to 13.06 percent recorded during the 2022 legislative polls.

Former president Nicolas Sarkozy, Greens party leader Marine Tondelier and former prime minister and Macron ally Edouard Philippe were among the first high-profile politicians to vote.

Philippe, the mayor of Le Havre in northern France who has made little effort to hide his ambitions for the presidency, was seen smiling and chatting to locals on Sunday morning.

Elections for the 577 seats in the National Assembly are a two-round process. The shape of the new parliament will become clear after the second round on July 7.

A woman casts her vote in the first round of parliamentary elections in Le Touquet, France, on Sunday. AFP

Most polls show the RN on course to win the largest number of seats in the National Assembly, parliament's lower house, although it remains unclear if the party will secure an outright majority.

Final opinion polls have given the RN between 35 percent and 37 percent of the vote, against 27.5-29 percent for the left-wing New Popular Front alliance and 20-21 percent for Macron's centrist camp.

If the RN obtains an absolute majority, party chief Jordan Bardella, Le Pen's 28-year-old protege with no governing experience, could become prime minister in a tense "cohabitation" with Macron.

Many analysts say that France is facing a hung Assembly, which could lead to deadlock and political instability.

Agence France-Presse