The French government has ordered all motorists to carry a breathalyzer in their car as of July 1. The government hopes the measure will bring down alchohol-related road deaths.
The new law requires all French motorists to carry an "unused and immediately available" breathalyzer test or face an on-the-spot fine, a decree published in the official gazette said on Thursday.
An unnamed road security official said drivers found without a breathalyzer would face a fine of 11 euros ($15), but only from November 1.
The law also affects drivers from other countries. Mopeds are the only motorized land vehicle exempted from the law.
Former President Nicolas Sarkozy promised the measure in November as a bid to reduce drink driving, which is behind 31 percent of fatal road accidents.
Disposable breathalyzers have been available in French bars and nightclubs since then.
When Sarkozy came to power in 2007, he said he wanted the government to reduce annual road deaths to 3,000 by 2012.
However, 3,970 people were killed on French roads in 2011, down barely 0.5 percent compared with the year before.
tj/msh (AFP, dpa)