Moderate and hardliner vie for French right nomination
Members of The Republicans are facing a relatively stark choice between Ile-de-France chief Valerie Pecresse, who would be the party's first-ever female presidential candidate and presents herself as a voice of moderation, and Eric Ciotti, whose views often reflect those of the far-right.
They made the run-off after the first round of voting earlier this week upended expectations, with the favourites ex-minister Xavier Bertrand and former EU Brexit negotiator Michel Barnier both knocked out.
Predictions are fraught with uncertainty as there has been no polling among the almost 140,000 party members who will pick the candidate. But analysts say Pecresse has the edge after both Barnier and Bertrand pledged her their support after losing.
The result is being keenly watched by the Elysee.
While all opinion polls have predicted centrist Macron should win the election, the emergence of a strong candidate on the traditional right who gains momentum during the campaign would be a major factor.
The campaign has so far been waged on the right, with Macron's government ticking rightwards over the last months with tough rhetoric on immigration and preserving France's secular system.
The Republicans failed to make the run-off in 2017, after its candidate Francois Fillon was felled by a graft scandal.
But the party, out of power since 2012, makes much of its status as the inheritor of the presidencies of Nicolas Sarkozy and Jacques Chirac as well as postwar leader Charles de Gaulle.
The winner will be announced at 1330 GMT by party leader Christian Jacob, half an hour after the electronic voting closes.
'I can beat Macron'
Pecresse is betting that rightwing voters are ready for her brand of conservatism that focuses on economic rigour as much as law and order concerns.
She has promised to "restore French pride" with a programme of budget cuts, immigration curbs, a defence of "family values" and a crackdown on crime and insecurity.
"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 after making the second round.
"I am the only person who can beat Emmanuel Macron. I am a woman who wins and acts," she added.
Ciotti, meanwhile, has long argued for radical policy "disruptions" to protect a France he deems at risk of losing its identity from immigration and economic decline.
'French Guantanamo'
Vowing to crack down on insecurity and the Islamist jihadist attacks that have rocked the country in recent years, Ciotti has warned of a "war of civilisations" and promises a "French Guantanamo" to hold suspected terrorists.
His rhetoric has sometimes echoed that of the far-right pundit Eric Zemmour, who declared his candidacy this week. Ciotti said he would vote for Zemmour in a run-off against Macron.
The announcement of the Republicans candidate will mean that the main contours for the April 2022 election are largely set.
Macron has yet to declare but it widely expected to seek re-election. Analysts believe he may wait several more weeks before showing his hand to stay above the fray of day-to-day politics.
His main rival in the 2017 election, far-right leader Marine Le Pen is standing again, while Zemmour's candidacy is a wild card move that could yet have a major impact or simply fizzle out.
The left remains mired in disunity and communication problems, with the campaigns of the Socialist candidate, Paris mayor Anne Hidalgo, and Green candidate Yannick Jadot failing to make an impact. Both risk being outpolled by far-left leader Jean-Luc Melenchon.