Masks will be compulsory for people aged 11 and over in crowded areas in Ile-de-France – Paris and its surrounding areas, starting from Monday morning, the prefecture announced on Saturday.

"All the indicators show that since mid-July the virus is again circulating more actively in the region," stated the prefecture, adding that this order will remain in place for one month.

The precise mapping of the areas will be disclosed on Sunday evening. In Paris, it will involve tourist sites, open markets, areas around stations, banks of the Seine and of Canal Saint-Martin and other places where social distancing is difficult, police of the French capital said in a post on Twitter.

Earlier in the week, the Paris City Hall had announced it was considering a mandate for people to wear masks in busy outdoor public spaces after the central government gave local authorities the power to toughen up rules to help reduce the spread of the coronavirus during the summer holidays.

Many French cities have already imposed mask-wearing in outdoor places. Anyone who refuses to comply with the rule will pay a fine of 135 euros (159 U.S. dollars). Those who violate it more than three times within one month would face six months in prison.

On Friday, France reported 2,288 new coronavirus cases, the biggest daily spike since the end of April. Since May 9, when the French government started a gradual de-confinement, some 787 clusters have been detected, of which 288 remain active.