France plans to introduce legislation to toughen sanctions on undeclared protests in response to violent “yellow-vest” demonstrations, Prime Minister Edouard Philippe said on Monday in a hardening of the government’s stance on the unrest.

He spoke after rioters torched motorbikes and set barricades ablaze on Paris’s upmarket Boulevard Saint-Germain on Saturday, underscoring how protests against high living costs and President Emmanuel Macron have turned violent on the fringes.

“We need to preserve the right to demonstrate in France and we must sanction those who break the law,” Philippe told TF1 television.