The new rule, announced by local authorities on Wednesday evening, entered into effect on Thursday morning.
The blanket measure was an extension of already existing rules on mask-wearing in certain streets of Nice, which is the seventh most populous city of France.
The decision was made by the Aples-Maritimes départment in response to a request by Nice Mayor Christian Estrosi to embrace a coherent approach for the city.
“To remain consistent in our fight against Covid-19 and to eradicate any doubts about the scope of wearing a mask, I would like to make mask-wearing compulsory everywhere in Nice,” Estrosi had said in a press statement.
— Christian Estrosi (@cestrosi) August 19, 2020
Masks have become a key preventive measure in France's attempt to stem what over the past week has been a rapidly increasing spread of Covid-19 across the territory.
Instead of introducing a blanket measure on mask-wearing outdoor everywhere in France, Prime Minister Jean Castex urged local authorities to extend their rules “as far as possible,” adapting local rules to local conditions.
Around 400 communes have so far brought in rules on masks in outdoor spaces, piling on the nationwide law that requires everyone to wear face-masks on public transport and indoors in public places, on pain of a €135 fine.
Some towns have specified certain areas, such as the historic walled town of Saint-Malo, while others have specified busy areas such as main shopping streets and outdoor markets.
Toulouse, France's second largest city, announced similar rules to Nice on Wednesday, but limited mask-wearing in the streets to between 7am and 3am.
Currently Nice has not made any time exemptions.
In Paris authorities first brought in a complicated system where masks were compulsory on 102 named streets. After much complaint, from August 15th a slightly less complicated system was brought in, where masks are compulsory in 37 zones but not in the whole city.