French Republicans choose their presidential candidate this week, who will challenge Emmanuel Macron in the spring.

Like all French elections, the primary is held in two rounds. Five candidates have qualified.

Here’s what you need to know.

How the primary works

Around 150,000 Republican party members are eligible to vote (electronically).

The results of the first round are announced on Thursday. The two candidates who receive the most votes go to a runoff on Saturday.

The winner will vie for second place in the opening round of the presidential election in April. Every poll taken in the past four years has put Macron in first place.

Different from 2016

In 2016, Republicans and smaller center-right parties experimented with an American-style open primary. All self-proclaimed center-right voters could participate. 4.4 million did.

The social conservative François Fillon prevailed, beating the more centrist former prime minister, Alain Juppé, and the right-wing former president, Nicolas Sarkozy.

He turned out to be a fraud. After the primary, it was revealed Fillon had paid his wife, Penelope, hundreds of thousands of euros in public money over the years for a fake job. Fillon placed third in the election, behind Macron and the far-right Marine Le Pen, with 20 percent support; an historic low for his party. Fillon has since been convicted and sentenced to five years in prison.

This year, only paid-up Republican party members are allowed to vote.

Candidates

• Michel Barnier, former French foreign minister, former European commissioner and the EU’s Brexit negotiator.
• Xavier Bertrand, former labor minister and president of the northern Hauts-de-France region.
• Éric Ciotti, lawmaker from Alpes-Maritimes in the south of France.
• Philippe Juvin, former member of the European Parliament and mayor of La Garenne-Colombes, a suburb of Paris.
• Valérie Pécresse, former budget minister and president of Île-de-France, the Paris region.

Barnier is an old-school patrician French politician, who has surprised liberal admirers by calling for an immigration stop. Bertrand is an everyday-man conservative, who can appeal to a segment of Le Pen’s blue-collar voters. Pécresse is a Thatcherite. Ciotti and Juvin are also-rans.

Who is the favorite?

Polls give Bertrand the best chance of qualifying for the second round of the presidential election in April, especially if Le Pen splits the far-right vote with the Trump-like Éric Zemmour.

Of the Republican candidates, Bertrand also polls best against Macron.

Barnier and Pécresse have garnered more endorsements from Republican party politicians.