Protesters from the Yellow Vests movement clashed with police on Saturday in the French city of Toulouse, days after a new law aimed at cracking down on riots came into force.
Police in the south-western city confirmed to dpa that arrests had been made, but could not immediately say how many.
Broadcaster FranceInfo reported that police charged at protesters, fired tear gas, and protesters set fire to a trailer parked on a street.
In Paris, protests by Yellow Vests and other groups opposed to the new law remained calm by mid-afternoon, though police said they made 15 arrests and carried out 5,885 checks on persons and vehicles.
The law, pushed through by President Emmanuel Macron’s centrist government after repeated violence at Yellow Vests protests, gives police more search powers in the vicinity of protests.
It also imposes penalties of up to a year in prison for persons covering their faces at protests without a legitimate reason.
But France’s Constitutional Council struck down a key measure that would have allowed senior government officials to ban individuals from taking part in protests if they were suspected of violence.
The Yellow Vests movement, which started in November in opposition to planned fuel tax rises, has since raised broader demands around tax, pay, and direct democracy, as well as calling for Macron to resign.
Macron is expected to announce new policies shortly based on contributions to a “great national debate’’ that he launched in response to the protest movement.