Some carried placards with the Anarchist symbol and banners with references to the far left "black bloc" protesters who regularly clash with police at international summits. Along the route of the march they looted and set fire to a McDonald's restaurant and also torched a car, a mechanical digger and a scooter. The police used tear gas and water cannon to try disperse them.
At least two people were arrested over the unrest, which comes at a time of heightened tensions over President Emmanuel Macron's reform of the public sector. "Macron makes us mad," read a banner held by one masked demonstrator. Interior Minister Gerard Collomb condemned the violence. "Everything is being done to end this serious disturbance to the peace an find those responsible for these unspeakable acts," he tweeted.
Trade unions had set out to try rally workers on May Day against Macron's reforms of state rail operator SNCF and public universities, which they see as part of a rollback of France's cherished public service. Tens of thousands of people took part in marches nationwide, including over 20,000 in Paris, the police said.
Some of the participants took aim at Macron's fiscal policy, seen as favouring business and the rich over the working- and middle classes. "Macron is the president of the rich," Genevieve Durand, a retired public servant who took part in a march in the central city of Clermont-Ferrand told AFP, echoing a label that has clung to the 40-year-old centrist.