Now French police have another weapon to wield against holidaymakers a law insisting all motorists have a breathalyser kit in their cars. The gadgets, designed so that drivers can test themselves to ensure they are under drink-drive limits, are the latest addition to a list of rules for driving on the other side of the Channel. Motorists travelling to France after July will be legally required to carry a breathalyser kit in the car The measure, which will come into force in July, will apply to anyone travelling through France by car. Critics however have cast doubt on the accuracy of the kits in being able to tell if a driver is over the limit. Others said it was simply another attempt to make money out of foreign drivers.