France has issued a decree banning certain homemade masks from being worn in public, saying they do not offer sufficient protection from the newer, more contagious Covid-19 variants.

Olivier Véran, the health minister, said a decree published on Friday came after recommendations from the country’s health experts.

“The high council for public health recommends, as do I, that the French do not masks they have made at home,” Véran said. He said the advice also covered industrially made fabric masks with lesser filtering qualities, listed as category 2.

On Monday, France’s junior minister responsible for health at work confirmed that official advice was to be changed to stop people wearing homemade masks in the workplace.

“The government is scrupulously following the recommendations of the High Council for Public Health and has done so since the beginning of this crisis,” Laurent Pietraszewski told Franceinfo radio.

He said the new health protocol in the workplace would be adapted “as usual, after discussions with the unions”.

Only three types of masks will be recommended: surgical, the FFP2 and fabric masks made to category 1 standards.

The recommendation has been criticised by the French Academy of Medicine that says there is a lack of scientific proof that homemade masks do not offer sufficient protection if worn properly.

The French authorities have admitted the new decree will be difficult to enforce.

“I don’t imagine the police are going to be asking people the protection level of their mask,” a spokesperson for the prime minister said.