Pollution hit a 10-year high in December and the alarm was sounded again in the Paris region and other parts of France this weekend, leading the authorities to order traffic restrictions to start on Monday morning.
Up until now they have been based on vehicles' licence plate numbers, alternating between odd and even numbers, but since 16 January motorists in Paris and 69 surrounding towns should have been displaying a sticker indicating how dirty their cars' emissions are.
The new ban is on the most polluting vehicles - those with diesel engines and those who are more than 16 years old - and the sticker should tell police whether a car is in these categories.
The only problem is that most drivers have yet to acquire the stickers.
The authorities say that 20-25 percent of vehicles either have them or will do soon.
But demand has outstripped supply and police have been ordered to take a "pedagogical" approach, warning motorists at first, rather than immediately imposing a fine that will become mandatory later.
Public transport cheaper, not free
A limit on the use of woodburning stoves will also be reinstated as will a free day's use of the Vélib bike-share scheme and a free hour for Autolib electric cars.
But public transport will not be free of charge, as it was during previous pollution peaks.
Because of objections by the right-wing-controlled regional council, there will be a fixed one-day charge instead.
Pollution in Lyon, storms in Corsica
The central city of Lyon, parts of the Alps, the eastern Vosges and some of the north of the country have also been affected.
Lyon, which introduced the stickers before Paris, has also brought back transport restrictions and most areas have tightened speed limits.
The cold snap has affected the whole country to a greater or lesser degree and torrential rain and winds of up to 100 km/hr have hit the east of Corsica and part of the mainland's Mediterranean coast.
Weather-watcher Météo France issued a flood warning for the mountainous Mediterranean island for Sunday and Monday.