Clashes have erupted at a protest by fairground workers in the French city of Le Mans, who are demanding the right to set up stall in the town centre, reports BBC News.
Police pushed back hundreds of demonstrators as rioters targeted the city hall, where staff were evacuated. There are reports of injuries.
Rioters pushed a burning caravan at police who fired rubber pellet grenades into the crowd, French media say.
At one point protesters occupied the city's railway station.
The violence broke out on the fourth day of protests against a decision by the mayor, Stéphane Le Foll, to move their fairground away from the city centre. Fairground workers accuse the city authorities of discrimination.
Monday's riots in Le Mans echo violent street protests at the cost of living which have gripped French cities every Saturday since mid-November - the "yellow vest" movement.
Police acted to drive back between 300 and 500 protesters in the north-western city, AFP news agency reports.
The trouble began around 6am when protesters set fire to containers and tyres. They also blocked off a road to a major shopping centre.
A crowd approached the police guarding the mayor's office, with masked rioters carrying baseball bats among them. Some protesters wore gas masks and protected themselves with improvised shields.
Police fired rubber pellet guns and at least one protester could be seen using a catapult.