In Paris, police estimated 75,000 people had responded to a call from unions, associations and a new left-wing political coalition formed for the parliamentary elections.

The CGT union put the figure at 640,000 protesters at a total of 182 rallies including 250,000 in Paris.

From Bayonne in the southwest to Nice in the southeast, from Vannes in the west to Reims in the east, demonstrators mobilised against the prospect of a victory for the far right in the legislative elections.

READ ALSO: IN PICTURES: Hundreds of thousands protest against far right in France

If that were to happen, National Rally (RN) party leader Jordan Bardella could become prime minister.

The RN enjoyed a healthy lead in recent election polls.

“I thought I would never see the far right come to power and now it could happen,” said Florence David, 60, who took part in the Paris protest.

“No need to vote RN to love France,” was among the slogans used.

The marches took place mostly in calm, but police arrested 20 people, including nine in Paris.

Five police officers were lightly injured in the protests.

There were brief episodes of tension in Rennes and Nantes in western France where a few dozen hard-left activists were pushed back by the police with tear gas.

In Paris, street infrastructure was damaged and two bank branches were targeted by hooded protesters.

Police in the capital were also the target of thrown bottles, to which they responded with tear gas, AFP correspondents said.

Some 21,000 members of the security forces were deployed across France.