Paris is notorious for snarled-up traffic and cranky drivers - but cars are gradually being edged out as the city steps up a life-or-death battle to cut pollution.

A stroll along the French capital's grandest boulevard, the Champs-Elysees, has just become possible without choking on exhaust fumes - from May cars are banned on the famous avenue one Sunday every month.

Pedestrians have already reclaimed part of the picturesque Left Bank of the River Seine, where traffic has been permanently banned, allowing restaurants, cafes and art exhibits to spring up.