Six out of ten drivers (59%) heading for France are still unaware of a new requirement to carry breathlyzers, according to a survey by Halfords. The law, which is aimed at ensuring drivers know whether or not they are below the French limit of 50 milligrams per 100 millilitres of blood, came into force this week. That limit is already 30mg lower than the UK's. However it could be risky checking immediately after emerging from the restaurant or bar. At least one expert has warned alcohol levels can be higher around 45 minutes later than immediately after downing your last glass of wine. According to the AA the new regulation will not be enforced until November 1, when you'll be fined €11 if you're caught without at least one unused breathalyser carrying the French NF certification mark. It will have to be valid within a date range. Single use breathalyzers are usually valid for a maximum of 12 months, through you can spend more and buy a multi-use digital version. The AA is selling the former in packs of two at its shops at the port of Dover and the Ashford Channel Tunnel terminal.