President Emmanuel Macron said on Tuesday that mask-wearing would be mandatory in places such as shops from Aug. 1, citing signs that the coronavirus was "coming back a bit".

But on Thursday Prime Minister Jean Castex said the order would take effect next week. Until now, it has been mandatory to wear face coverings only on public transport and in public spaces where social distancing is not possible.

"We were considering implementing (this measure) on August 1," Castex told the Senate. "I have heard and understood that this deadline appeared late or raised some questions, so the decree will come into force next week."

Health Minister Olivier Veran, speaking in the lower house of parliament, encouraged people to start wearing masks now, without waiting for the decree, calling wearing masks a matter of social responsibility.

Official figures show the number of COVID-19 infections and fatalities has slowed in France since late May. The disease has killed more than 30,000 people in France and is spreading again in some areas.

The Mayenne prefecture in the northwest said the wearing of face masks was now compulsory in its main city, Laval, and five other municipalities - Bonchamp-lès-Laval, Changé, L’Huisserie, Louverné and Saint-Berthevin.

There has been a localized flare-up of COVID-19 cases in the region, and it has now been re-classified by the health ministry as a zone of heightened risk.

Macron also said on Tuesday that he wanted coronavirus testing available for everyone, without having to be referred by a doctor. He said the expected job losses because of the pandemic posed a major challenge.