Paris' most famous boulevard, the Champs-Elysees, will be off-limits to cars on the first Sunday of every month starting in May, Paris city hall said Monday.

The first pedestrian-only day will be May 8 instead of May 1, a public holiday, when many of the council workers needed to run the scheme will be off work, Nayor Anne Hidalgo's office said.

From then on, cars will be banished from the two kilometre-long (1.2-mile) street on the first Sunday of every month when museums in Paris are also free to the public.

Nine new routes will also be pedestrianised every Sunday and public holiday -- adding to the 13 already subject to traffic restrictions under the "Paris Respire" anti-pollution programme.

Hidalgo, a Socialist, has made fighting the smog that periodically shrouds the French capital one of her top priorities.

The World Health Organization says fine-particle air pollution is responsible for about 42,000 premature deaths in France each year.