France plans to introduce new legislation to punish protesters after seven weeks of violent “yellow vest” demonstrations.
Prime Minister Edouard Philippe spoke after rioters torched motorbikes and set barricades on fire on Paris's upmarket Boulevard Saint-Germain on Saturday.
He said on Monday that 80,000 members of the security forces would be deployed for the next wave of protests.
The Prime Minister told TF1 television: "We need to preserve the right to demonstrate in France and we must sanction those who break the law.
"That's why the government favours updating the law in order to sanction those who do not respect this obligation to declare protests, those who take part in undeclared protests, those who arrive at protests with balaclavas.”
He said the government could model the new law on existing legislation against football hooligans, which can lead to supporters being banned from stadiums.
It could be introduced as soon as February, he said.
The "yellow vest" movement, which takes its name from the fluorescent safety vests French motorists must all have in their vehicles, emerged in mid-November as a protest against fuel tax increases.
It soon morphed into an expression of rage about the high cost of living in France and a sense that President Emanuel Macron's government is detached from the everyday struggles of workers.
Mr Philippe also said the thugs who have looted shops and vandalised banks would be forced to pay for the damage they cause.
The latest gilet jaunes marches on Saturday began peacefully but quickly descended into chaos, with protesters hurling missiles at riot police and blocking bridges over the Seine.
Officers fired tear gas to prevent protesters crossing the river and reaching the National Assembly.
One riverboat restaurant was set ablaze and a policeman was wounded when he was hit by a bicycle hurled from a street above the river bank.
