UK holidaymakers driving in parts of France this summer risk being fined if they do not buy a windscreen emissions sticker before their trip.
The RAC said the number of areas across the country which require drivers to display a Crit’Air sticker rose to 12 last month, with the addition of Bordeaux and Clermont-Ferrand.
Motorists who fail to abide by the rule face a fine of 68 euros (£58), which rises to 180 euros (£154) if not paid within 45 days.
Fines will increase to up to 750 euros (£640) from next year when camera-based enforcement begins.
Crit’Air stickers cannot be bought locally. They must be ordered in advance from a French government website at a cost of 4.61 euros (around £4).
The RAC urged drivers to avoid third-party websites that charge up to six times as much.
There are six different types of stickers, based on a vehicle’s air pollutant emissions.
The cleanest electric and hydrogen vehicles require green “0” stickers, while at the opposite end of the spectrum, the most polluting diesel vehicles need “5” stickers.
Some areas of France restrict vehicle movements based on their sticker.
The RAC warned that other European countries such as Spain and Switzerland also have increasingly strict emissions regulations.