Paris, in an effort to ease dangerous pollution levels, is allowing only cars with license plates that end in odd numbers on the road Monday.
Vehicles with even license plate numbers are designated to be the only ones on the road Tuesday, if the pollution levels remain high after Monday.
Seven-hundred police have been deployed across Paris and 22 surrounding areas of the French capital to enforce the measure.
Electric and hybrid cars are exempted from the ban, as well as any vehicle carrying three or more people.
Officials said this is the first time the alternate driving day scheme has been enforced since 1997.
City officials announced the move Saturday after air pollution reached unsafe levels.
Public transportation was made free over the weekend to persuade residents to leave their cars at home.
The smoggy conditions have been caused by a combination of cold nights and warm days, preventing the pollution from dispersing.