France's conservative party on Thursday chose the moderate chief of the Paris region and a hardline MP with controversial views on immigration to run for its nomination in the 2022 election where President Emmanuel Macron is expected to seek a second mandate.

Valerie Pecresse, who heads the greater Paris region and MP Eric Ciotti from the southern city of Nice, won the first round of the Republicans primary and will now face off in a second vote whose results will be announced Saturday.

The voting by party members presented a major disappointment for Michel Barnier, the EU's former negotiator on Brexit, who was knocked out of the contest after finishing in third place, and the fourth-placed heavyweight ex-minister Xavier Bertrand.

If chosen on Saturday, Pecresse would be the first female candidate for the presidency for the Republicans (LR), which traces its lineage to rightwing presidents Jacques Chirac and Nicolas Sarkozy, and an intriguing entry into the presidential race.

Ciotti, meanwhile, has views far closer to the far-right which have sometimes echoed those of Eric Zemmour, the controversial pundit who declared his candidacy on Tuesday.

Pecresse was given an immediate boost ahead of the next round of the vote after all three losing candidates including Barnier backed her rather than Ciotti.

"I bring a programme of real change as France has no more time to lose after Macron's term which has damaged and divided France so much," Pecresse said.

"I am the only person who can beat Emmanuel Macron. I am a woman who wins and acts," she added.

Analysts view the primary outcome as crucial to the shape of the election, which polls show Macron is currently a clear favourite to win, though the centrist former investment banker has not yet confirmed a re-election bid.

The April 2022 vote looks set to be dominated by concerns about immigration and security, and with Macron hoping to benefit from his handling of the pandemic with vaccination rates higher and fewer restrictions than in some other European countries.

Valerie Pecresse, left, and Eric Ciotti won the first round of the Republicans primary. Valerie Pecresse, left, and Eric Ciotti won the first round of the Republicans primary. Photo: AFP / Joël SAGET

The results were close for the four leading candidates, with Ciotti garnering 25.6 percent and Pecresse 25.0 percent, followed by Barnier (23.9 percent), Bertrand (22.4 percent) and the outsider Phillipe Juvin, a mayor and doctor who rose to prominence during the Covid pandemic (3.1 percent).

Bertrand, who like Pecresse abandoned the Republicans in 2017 after accusing the party of adopting far-right tropes, said on Twitter that he would vote for Pecresse.

Barnier also said on Twitter that he thought Pecresse "was the best prepared to win the presidential election. I give her my support," adding he was proud to have fought a "respectful" campaign.

The results were a major personal setback for Barnier, who won admirers for his deft handling of the Brexit negotiations but troubled some fans with his hard line during campaigning that included a call for a moratorium on immigration.

Stakes are high for the Republicans after a bitterly divisive primary ahead of the 2017 presidential election, when it was outflanked by the veteran far-right candidate Marine Le Pen.

They are again facing a challenge by Le Pen's National Rally as well as the wild-card candidacy of Zemmour, with both accusing Macron of failing to counter illegal immigration and the threat of Islamist terrorism on French soil.

Macron is also pushing hard to win over traditional conservatives to his pro-business plank, pledging to push ahead with ambitious economic and labour reforms that appeal to the Republicans' base.

A series of televised debates did not produce a clear primary front-runner, with the outcome in doubt until announced by LR leader Christian Jacob.

But Ciotti, whose views are often close to those of the far right, stood out in the debates with pledges to crack down hard on immigration and to create a "Guantanamo" prison for Islamist terror suspects, as well as a sharply reduced flat tax of 15 percent for businesses.

Zemmour, who some polls have shown as a possible contender to reach a second-round run-off against Macron ahead of Le Pen, expressed his admiration for Ciotti after the results were published.

"I am happy, dear Eric, to see our ideas so widely shared by LR members," he said on Twitter.