Toulouse is France's fourth-largest city and officials there fear that a mass movement of people as the summer break draws to a close will lead to a spike in infections.
Hundreds of French towns have already made masks compulsory in some outdoor areas, but Toulouse is the first city to impose a blanket requirement for all outdoor spaces.
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.
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.
National laws make face masks compulsory on public transport and indoors in public places, on pain of a €135 fine.
But Prime Minister Jean Castex has encouraged local authorities to draw up their own regulations adapted for local conditions and so far around 400 communes have brought in rules on masks in outdoor spaces.
Toulouse officials said masks would be compulsory outdoors across the city starting on Friday, August 21st from 7am to 3am, for all people aged 12 and over, including those on bikes and scooters.
New infections across France have been increasing in recent weeks and the numbers of people admitted to hospital have been rising as well.
On Tuesday, Labour Minister Elisabeth Borne announced masks will be required in all shared, indoor workspaces starting next month, including in meeting rooms, corridors, change rooms and open-plan offices.
The coronavirus outbreak has claimed more than 30,400 lives in France so far.
After initially casting doubt on the value of masks as an infection barrier, the French government made a U-turn and have since the end of the nationwide lockdown in May recommended people use masks as a protective measure along with social distancing and regular hand sanitising.