Clashes erupted in Paris next to a Left Bank brasserie favoured by French President Emmanuel Macron as protesters torched garbage cans and smashed two banks during the eleventh day of nationwide demonstrations against pension reform.
The bistro La Rotonde, whose awning was set alight as protesters threw bottles and paint at police, is known in France for hosting a much-criticised celebratory dinner for Macron when he led the first round of the 2017 presidential election.
Protests against the flagship reform of Macron's second term, which lifts the retirement age by two years to 64, began in mid-January and have coalesced widespread anger against the president.
Labour unions on Thursday evening called for another day of nationwide protests on April 13.
"Strike, blockade, Macron walk away!" protesters chanted in the western city of Rennes, where police fired tear gas at protesters who threw projectiles at them and set bins on fire.
The street protests have become increasingly violent since the government pushed the pension legislation through parliament without a final vote due to a lack of support among lawmakers.
But police estimates indicate the number of people taking part may be falling.
On Thursday, black-clad anarchists smashed the windows of two banks and engaged riot police in cat-and-mouse skirmishes along the route of the street protest.
One police officer briefly lost consciousness after being struck on the helmet by a rock.
A total of 77 police force members were injured and 31 people were arrested as of 1820 GMT in Paris, police said.
Polls show a wide majority of voters oppose the pension legislation. But a source close to Macron said that was not what mattered.
"If the role of a president of the republic is to make decisions according to public opinion, there is no need to have elections," the source said. "Being president is to assume choices that may be unpopular at a given time."