While most British holidaymakers driving in France will give Paris a wide berth, a sizeable number will make a trip into the city - and they will now find they need to sign up to an emissions scheme, or that older cars may even be banned.
The categories correspond to the six European Union emission standards for cars – dating back to 1992 when Euro-1 was introduced.
RAC European breakdown spokesman Simon Williams said: 'Anyone caught without a sticker risks a fine of up to £117, although we understand the French police are likely to be lenient in the early days.
The Other Danish Guy's co-founder Matti Pesonen said: 'Most runners will happily talk about nipple rub.'But bum chafing is much more of a taboo subject - even though it happens a lot more than people might admit.
A new colour-coded car emissions sticker system has come into force in Paris - and if you don't have the correct one you face fines of between £58 and £117 (€68 and €135).
Chafing of the buttocks or the bottom crevice is a common affliction for runners and cyclists.
It's either caused by skin rubbing on clothing, or skin rubbing on other areas of skin, and it's exacerbated by excess moisture from sweating or during hot weather.
Vehicles that are deemed too polluting to fit into any of the bands – which includes petrol and diesel-powered cars registered before 1997 – will not be granted a sticker at all and are therefore banned from Paris during certain times.
These vehicles that fail to fit meet the emissions limits of even the highest Crit-Air group will not be allowed access to the capital between 8am and 8pm, Monday to Friday.
As well as these older cars, motorcycles and scooters registered before 2000 and buses and trucks before 2001 will also not be granted a vignettes.
The RAC said it believes that nine per cent of French vehicles are too old to get a sticker at all.
Mr Lähde said the idea came after he shared a hotel room with a close friend who was suffering from extreme bum chafing.