Riot police scuffled with protesters and fired tear gas to disperse crowds during a traditional May Day march in Paris on Saturday (May 1).
Debris fires burned, flares were fired and bank windows smashed in the French capital, where trade unionists were joined by members of the "Yellow Vest" movement, and workers from sectors hit hard by pandemic restrictions.
Thousands joined some 300 marches across France despite lockdown restrictions, demanding social and economic justice, and voicing their opposition to government plans to change unemployment benefits.
Arrests were made in the capital, where at least 5,000 police have been deployed, Parisian authorities told Reuters.
A few hooded, black-clad demonstrators clashed with police or threw stones and garbage bins.
Police said they had prevented 'Black Bloc' anarchists from forming a group.
President Emmanuel Macron won the presidency in 2017, promising a new way of doing politics.
But much of his reform agenda has been bogged down in fights with unions, while the pandemic has halted his plans to reform the pension system.
May Day protests could also been seen elsewhere in the world, including England's capital, London, where hundreds gathered to demonstrate against a proposed law that would give police extra powers to curb protests.
And marches were organized in some German cities by Neo-Nazis and the so-called Querdenker or "Lateral Thinker" anti-lockdown movement.