New motoring laws in France force drivers to carry breathalyser kits in their vehicles.
As of Sunday, motorists and motorcyclists will face an on-the-spot fine unless they travel with two single-use devices as part of a government drive to reduce the number of drink-drive related deaths.
The new regulations, which excludes mopeds, will be fully enforced and include foreigner drivers from November 1 following a four-month period of grace. Anyone failing to produce a breathalyser after that date will receive an 11 euro fine.
French police have warned they will be carrying out random checks on drivers crossing into France via ferries and through the Channel Tunnel to enforce the new rules.
Retailers in the UK have reported a massive rise in breathalyser sales as British drivers travelling across the Channel ensure they do not fall foul of the new legislation.
Car accessory retailer Halfords said it is selling one kit every minute of the day and has rushed extra stock into stores to cope with the unprecedented demand.
Six out of 10 Britons travelling to France are not aware they have to carry two NF approved breathalysers at all times, according to the company.
The French government hopes to save around 500 lives a year by introducing the new laws, which will encourage drivers who suspect they may be over the limit to test themselves with the kits.
The French drink-driving limit is 50mg of alcohol in 100ml of blood - substantially less than the UK limit of 80mg.