A breathalyser is a method of testing the proportion of alcohol in your breath. In the majority of the UK the current limit is 35 or a Blood Alcohol Content of 0.8 (In Scotland the BAC is 0.5) In France however the legal BAC limit is 0.5 and 0.2 for newer drivers.
In 2012 the French Government brought in a law which stated that motorists, driving in France must carry, in their vehicle an NF approved breathalyser. This was made compulsory in November 2012 and carried an on the spot fine for those not complying.
In early 2013 the French Government decided to postpone the implication of the fines for non compliance however the law still stands. This therefore means that although you will not be fined, you should still carry a breathalyser in your vehicle when travelling through France. We therefore suggest you keep one in the car just to make sure.