More than 47 million people are eligible to vote in the first round of a parliamentary election on Sunday to choose members of the National Assembly, the country's lower house of parliament.
Polls open at 8am (06:00 GMT). They will close, in the largest cities, at 8:00pm (18:00 GMT).
More than 50,000 police will be on patrol in a country still under a state of emergency following a wave of attacks that have killed more than 230 people since 2015.
Here are key facts to know as French voters head to the polls.
How do the parliamentary elections work?
There are 577 seats up for grabs, including 11 which represent more than 1.5 million French citizens living overseas.
Each constituency represents about 125,000 inhabitants.
If no candidate wins more than 50 percent in the first round on Sunday, the two top-placed go into a second round on June 18 - as well as any other candidate who won the votes of more than 12.5 percent of the local electorate.
A total of 7,882 candidates are standing nationwide in a process expected to see many fresh faces elected - not least because more than 200 outgoing members of parliament are not running for re-election.
The average candidate's age is 48.5 years and more than 42 percent are women. In the outgoing parliament, women represented only 26.9 percent of deputies, or 155 out of 577, which was itself a record.
What is expected to happen?
Since 2002, voters have consistently given new presidents a legislative majority.
Macron's predecessors - Francois Hollande in 2012, Nicolas Sarkozy in 2007 and Jacques Chirac in 2002 - all won outright majorities. Unlike Macron, however, they all came from long-established parties.
|The French flag flies atop the National Assembly building in Paris where French deputies debate and vote on laws [File: Charles Platiau/Reuters]|
Al Jazeera's Natacha Butler, reporting from Paris, said the likelihood of Macron's party winning a majority "really depends a lot on people coming out to vote".
She added that many in France "are simply suffering from election fatigue after a very long presidential campaign".
Macron is still heavily favoured to win a majority - a host of opinion polls show his party could take around 30 percent of the vote, putting it in pole position to secure an absolute majority in the second round a week later.
The centrist launched his En Marche! movement shortly before announcing he would run for president.
Macron, a former banker and economy minister, favours the European Union, is a fierce defender of an open immigration system and, unlike several of his opponents, has avoided making pronouncements against Muslim dress codes.
"Macron has been saying from the very moment he was elected as president that he needs this majority to implement the measures he promised during the election," Thomas Brisson, a Paris-based political analyst, told Al Jazeera. "[Since last month] when the National Front was still expecting to make big gains in this election, they have had to downsize those expectations."
What if Macron fails to win an absolute majority?
The media-savvy Macron is hoping to use the momentum from his presidential victory over seriously weakened traditional right- and left-wing parties to build a large majority in parliament.
His party is running candidates in the legislative elections as La Republique En Marche! (Republic on the Move, REM).
With half of REM's candidates coming from civil society, he hopes notably to tackle reform of the traditionally thorny issue of labour law.
If he fails to win an absolute majority - 289 out of 577 seats - it would complicate his job as president because he would have to build a coalition with right and left parties.
The far-right National Front of his defeated presidential rival Marine Le Pen and the radical left will both also be seeking to capitalise on the move away from established parties.
Who's in the running?
The Republicans: The party of ex-prime minister and scandal-wracked former presidential candidate Francois Fillon is hoping to take its revenge, even to impose a right-wing cohabitation on the centrist president. But with 50 of its MPs not standing again, it could lose more support to REM.
France Unbowed: The communist-backed Jean-Luc Melenchon scored 19.6 percent in the first round of the presidential ballot. His La France insoumise (France Unbowed) movement is putting up candidates in 500 constituencies, and hopes to win at least 15 seats in the National Assembly to form a parliamentary group.
National Front: Weakened after the poorer-than-expected score by Le Pen in the presidential run-off against Macron (33.9 percent), the National Front nonetheless wants to present itself as the main opposition after she secured 10.7 million votes in May.
|A ballot being cast in a polling station [Eric Gaillard/Reuters]|
The far-right party hopes to win at least in the 45 constituencies where Le Pen won more than 50 percent in the head-to-head on May 7.
But it could be an uphill battle, especially after her niece Marion Marechal-Le Pen withdrew from political life, dealing the party a blow in its southern heartland.
The party looks set to struggle to win 15 seats nationally, a score that would represent another deep disappointment
But Le Pen remains defiant, telling the AFP news agency this week that with other parties likely to agree to work with Macron, "we will be the only opposition force".
Socialist Party: The left-wing party that formed the previous government needs to avoid all-out collapse. After a historically low score in the first round of the presidential election - 6.3 percent for candidate Benoit Hamon - the stakes could hardly be higher.
Part of its electorate has left for Macron's, others for Melenchon's, party.
Some are already bracing for another bleak election night for a party which has long been one of the two mainstream forces in French politics. Veteran observers recall the debacle of 1993 which produced just 57 Socialist and allied deputies.
Source: Al Jazeera and news agencies