From 1 April, foreign motorists in Paris, Lyon and Grenoble must display an air-quality certificate known as CRIT’Air.
The certificate costs €4.18 and being spotted without one will incur a fine of €135.
The stickers should arrive within 30 days of ordering but as there will no doubt be an initial surge it would make sense to order sooner rather than later.
The six coloured stickers indicate the age and cleanliness of a vehicle. Cars are rated according to whether they are electric or hydrogen-powered, petrol or diesel cars, and how old they are.
Full details and to purchase if you are travelling to one of these cities – https://www.certificat-air.gouv.fr/en/