Prime Minister Mr Castex announced on Thursday July 16 that masks would be mandatory across France in indoor spaces from Monday 20th July.
The government had originally said the rule would be enforced from August 1 - as President Emmanuel Macron said in his July 14 speech - but this was then brought forward after many medical authorities and doctors called for masks to be mandatory as soon as possible.
This includes shops, banks, libraries, retail centres, covered markets, government buildings and offices, museums and tourist sites - in short any establishment that receives members of the public.
Shopping association la Fédération du Commerce et de la Distribution (FCD) confirmed that the rule would especially apply in food shops and supermarkets, including at Auchan, Aldi, Carrefour, Colruyt, Cora, Groupe Casino, Intermarché, Leclerc, Lidl, Netto, Supermarché Match and Système U.
The list also includes places of worship, hotels (in communal areas), covered sports facilities and temporary structures such as marquees.
The masks will be mandatory for everyone over the age of 11, but are prohibited for children under three. Children aged 3-11 only need to wear a mask if they have virus symptoms, for example if they are waiting to be collected from school after falling ill (but should then self-isolate completely once symptoms appear).
People will risk a fine of 135 euros starting for failure to comply with a new decree to wear a mask in public places indoors, the government announced.