Public transport was free in Paris on Monday and half of the city’s cars were forced off the road in a bid to fight pollution.
In a radical move which will be studied in other European capitals like London, French Socialists said everything had to be done to make air cleaner.
Anne Hidalgo, the mayor of Paris, said: ‘I am delighted the state has agreed to put in place a partial driving ban on Monday, which I have been requesting for several days.’
Only vehicles with number plates ending in an odd number were allowed, with exemptions for taxis, electric cars and ambulances.
Authorities were planning to ban cars with odd numbers on Tuesday, but the scheme was halted following improving forecasts.
Foreign visitors to Paris, including thousands of Britons on holiday, were also permitted to use their cars.
But police patrols were seen booking locals who flouted the ban, forcing them to return home. Meanwhile, Metro trains and buses were full to overflowing as thousands abandoned their vehicles.
Air quality monitors showed concentrations of potentially dangerous particulates in the Pars air were above the recommended maximum.
These are created by cars and lorries, heating and heavy industry, and can potentially cause serious health problems.
‘Due to the improving situation today and tomorrow, the alternative traffic (plan) will not be renewed Tuesday,’ announced Ecology Minister Segolene Royal, who took time to salute ‘the good citizenship of motorists who understood the necessity of this measure.’
The Airparif monitoring agency said smog density was still near alert levels Monday, but rain forecast for Tuesday was expected to clear the air.
Though public transport is free of charge to take the sting out of the restrictions, drivers in the capital have protested against the measure, despite it having been used only twice since 1997.
Similar emergency restrictions were last implemented almost exactly a year ago – on March 17 – during a particularly bad spike in the pollution levels.
Authorities measure the concentration of particulates with a diameter of less than 10 microns – so-called PM10 – in the air to determine pollution levels.
The safe limit for PM10 is set at 80 micrograms per cubic metre (mcg/m3), with levels in Paris Monday expected to be somewhere between 40 and 55 mcg/m3.
The city’s alert level is fixed at 50 mcg/m3.
According to a 2011 World Health Organisation report, the planet’s most polluted city was Ahvaz in Iran with an average of 372 mcg/m3.
Beijing had an average of 121 mcg/m3, while Paris was measured at 38 mcg/m3.