French voters are being called to the polls on Sunday for an exceptional moment in their political history: the first round of snap parliamentary elections that could see the country’s first far-right government since the World War II Nazi occupation — or no majority emerging at all.

The outcome of the vote, following the second round on July 7 and an hasty campaign, remains highly uncertain as three major political blocs are competing: the far-right National Rally, President Emmanuel Macron’s centrist alliance and the New Popular Front coalition that includes center-left, greens and hard-left forces.

Here’s a closer look:

How does it work?

The French system is complex and not proportionate to nationwide support for a party. Legislators are elected by district. A parliamentary candidate requires over 50% of the day’s vote to be elected outright Sunday.

Failing that, the top two contenders, alongside anyone else who won support from more than 12.5% of registered voters, go forward to a second round.

In some cases, three or four people make it to the second round, though some may step aside to improve the chances of another contender — a tactic often used in the past to block far-right candidates.

Key party leaders are expected to unveil their strategy in between the two rounds. This makes the result of the second round highly uncertain, and dependent on political maneuvering and how voters react.

The far-right National Rally, ahead in all pre-election opinion polls, hopes to win an absolute majority, or at least 289 out of the 577 seats.

The National Assembly, the lower house, is the more powerful of France’s two houses of parliament. It has the final say in the law-making process over the Senate, dominated by conservatives.

Macron has a presidential mandate until 2027, and said he would not step down before the end of his term.

What’s cohabitation?

If another political force than his centrist alliance gets a majority, Macron will be forced to appoint a prime minister belonging to that new majority.

In such a situation — called “cohabitation” in France — the government would implement policies that diverge from the president’s plan.

France’s modern Republic has experienced three cohabitations, the last one under conservative President Jacques Chirac, with Socialist Prime Minister Lionel Jospin, from 1997 to 2002.

The prime minister is accountable to the parliament, leads the government and introduces bills.

“In case of cohabitation, policies implemented are essentially those of the prime minister,” political historian Jean Garrigues said.

The president is weakened at home during cohabitation, but still holds some powers over foreign policy, European affairs and defense because he is in charge of negotiating and ratifying international treaties. The president is also the commander-in-chief of the country’s armed forces, and is the one holding the nuclear codes.

“It’s possible for the president to prevent or temporarily suspend the implementation of a certain number of the prime minister’s projects, since he has the power to sign or not sign the government’s ordinances or decrees,” Garrigues added.

“Yet the prime minister has the power to submit these ordinances and decrees to a vote of the National Assembly, thus overriding the president’s reluctance,” he noted.

Who leads defense and foreign policies?

During previous cohabitations, defense and foreign policies were considered the informal “reserved field” of the president, who was usually able to find compromises with the prime minister to allow France to speak with one voice abroad.

Yet today, both the far-right and the leftist coalition’s views in these areas differ radically from Macron’s approach and would likely be a subject of tension during a potential cohabitation.

According to the Constitution, while “the president is the head of the military, it’s the prime minister who has the armed forces at his disposal,” Garrigues said.

“In the diplomatic field also, the president’s perimeter is considerably restricted,” Garrigues added.

The National Rally’s president, Jordan Bardella, said that if he were to become prime minister, he would oppose sending French troops to Ukraine — a possibility Macron has not ruled out. Bardella also said he would refuse French deliveries of long-range missiles and other weaponry capable of striking targets within Russia itself.

If the leftist coalition was to win the elections, it could disrupt France’s diplomatic efforts in the Middle East.

The New Popular Front’s platform plans to “immediately recognize the Palestinian state” and “break with the French government’s guilty support” for Israeli Prime Minister Benjamin Netanyahu’s government.

Macron previously argued the recognition of the Palestinian state should take place at a “useful moment,” suggesting the Israel-Hamas war doesn’t not allow such a move at the moment.

What happens if there’s no majority?

The president can name a prime minister from the parliamentary group with the most seats at the National Assembly — this was the case of Macron’s own centrist alliance since 2022.

Yet the National Rally already said it would reject such an option, because it would mean a far-right government could soon be overthrown through a no-confidence vote if other political parties join together.

The president could try to build a broad coalition from the left to the right, an option that sounds unlikely, given the political divergences.

Experts say another complex option would be to appoint “a government of experts” unaffiliated with political parties but which would still need to be accepted by a majority at the National Assembly. Such a government would likely deal mostly with day-to-day affairs rather than implementing major reforms.

If political talks take too long amid summer holidays and the July 26-Aug. 11 OIympics in Paris, Garrigues said a “transition period” is not ruled out, during which Macron’s centrist government would “still be in charge of current affairs,” pending further decisions.

“Whatever the National Assembly looks like, it seems that the Constitution of the 5th Republic is flexible enough to survive these complex circumstances,” Melody Mock-Gruet, a public law expert teaching at Sciences Po Paris, said in a written note. “Institutions are more solid than they appear, even when faced with this experimental exercise.”

“Yet there remains another unknown in the equation: the population’s ability to accept the situation,” Mock-Gruet wrote.