Trade unions and left-wing parties on Saturday staged demonstrations across France to protest against the rise of the far right, which recent polls suggest could emerge as the leading political force in the upcoming elections.

Security forces reported that some 250,000 people took to the streets nationwide, including 75,000 in the capital Paris.

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.

Meanwhile, the General Confederation of Labour (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 mobilized against the prospect of a victory for the far right in snap legislative elections that President Emmanuel Macron called following the right-wing's dominance in European Parliament elections.

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

Following the initial results indicating defeat for his coalition against the far-right National Rally (RN) in the European elections, Macron dissolved the lower house of the National Assembly and scheduled snap elections on two rounds – June 30 and July 7.

In the conclusive outcome of the European Parliament elections, the RN secured 31.37% of the votes in France, whereas Macron's Renaissance party and its allies garnered a mere 14.6% of the votes. 

Saturday's 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 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.

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

Read more: Macron calls for anti-far right coalition ahead of French elections