France has made face masks compulsory in all enclosed public spaces amid a fresh bout of Covid-19 outbreaks.
Masks were already mandatory on public transport, but from Monday they must also be worn in places like shops.
Health Minister Oliver Véran warned that France had between "400 and 500 active clusters" of the virus.
President Emmanuel Macron declared a "first victory" over the virus in June and has ended the national state of emergency, but local outbreaks remain.
There are a rising number of cases in the north-west and in eastern regions, in particular in the north-western department of Mayenne.
France, one of Europe's hardest-hit countries, has recorded more than 200,000 infections and over 30,000 deaths since the start of the pandemic.
Face masks are now compulsory in all enclosed public spaces, including shops where previously owners were able to decide themselves whether customers should wear coverings or not. Anyone caught without a mask faces a fine of €135 (£123; $154).
Authorities in Mayenne began calling for mandatory mask restrictions last week as cases soared in the department.
Public health agency Santé Publique France issued a warning for Mayenne after it passed the alert threshold of 50 new cases per 100,000 inhabitants in a week. Across France as a whole, that figure is about 10 per 100,000 inhabitants.