Paris car ban: 'Most people are playing the game'
17 March 2014 Last updated at 09:18 GMT
Hundreds of police are monitoring traffic in Paris after pollution levels prompted the French government to impose major restrictions.
Only motorists with cars that have odd-numbered registration plates should use their vehicles on Monday. On Tuesday, if the restrictions remain in place, it will be the turn of those with even-numbered plates.
The BBC's Hugh Schofield said he had seen some motorists defying the rules but that "most people appear to be playing the game".