The Mayor of Paris is about to launch another novel scheme for fighting congestion and pollution: self-service cars.

Bertrand Delanöe aims to start with 2,000 electric-powered vehicles that subscribers can drive off without booking at dozens of sites 24 hours a day and then leave anywhere in the city.

The so-called Automobiles-en-Libre-Service would greatly expand on similar small-scale services that exist in Europe and America. It is intended to complement the Vélib, the highly successful bicycle scheme that Mr Delanöe opened last July with 5,000 rental stations around the city.

The non-polluting cars, which will cost a few euros per hour to use, depending on mileage, will enable Parisians to carry passengers and loads on short trips without the bother and expense of hiring or running their own vehicles, says the mayor.

They will offer an alternative to a congestion charge, which Mr Delanöe, a Socialist who is running for reelection next spring, has rejected for Paris.

Just as the bicycle scheme was greeted with scepticism, doubts are being sounded over the viability of the Voiturelib’ – free car – as it is being dubbed. Denis Baupin, the Green Party deputy to Mr Delanöe, is worried that Parisians could drop their new-found cycling habit. “Vélib users shouldn’t be encouraged to take a car instead of a bike,” he said. Some experts are also questioning whether the cars, which would be many times more expensive to operate than bicycles, could be subsidised through advertising space, like the Vélib.

Mr Delanöe’s team calculates that one car will replace between five and ten private vehicles. Only 43 per cent of Paris households have vehicles and 95 per cent of them are parked at any moment.

Mr Delanöe, who is France’s most popular Socialist and a likely presidential candidate, is expected to make a splash with details of the scheme this month, as part of the launch of his campaign for reelection in March municipal elections. The mayor, who aims to make Paris a world eco-capital, is seen as the distant favourite against Françoise de Panafieu, the candidate for the Union for a Popular Majority, President Sarkozy’s party. Mrs de Panafieu has produced her own plan for 2,500 self-service cars.

Mr Delanöe’s Vélib has turned Paris into an almost bike-friendly city, with the 20,000 machines having already been used for 11 million trips so far. Parisians and commuters relied on them during transport strikes in November.

Mr Delanöe is threatening penalties against JC Decaux, the advertising firm that operates them, because so many are out of service or in disrepair from overuse and vandalism. Decaux, which has been given a monopoly on advertising space in return for the bicycle system, has been unable so far to ease the problem of saturation in Paris when commuters arrive in the morning. The lack of docking space deters many Parisians from picking up Vélibs for the ride to work.

The city is also running a safety campaign after the first Vélib death, a woman in her fifties who was crushed by a lorry last month.

Mr Delanöe, who gets around Paris in a tiny electric-powered Citroën Saxo, has already promoted a more limited auto-partage (car-sharing) scheme. Three companies are offering 133 mainly petrol-driven vehicles from 25 stations for hourly rental. They have about 2,000 subscribers.

The city is looking at two possible new-generation electric vehicles. One, called the Blue Car project, is a three-seater capable of travelling 156 miles between charges. The other, Cleanova, developed by the Dassault aviation firm, uses the body of the small Renault Kangoo van.

Cleaner motoring from bright sparks

— The Cleanova II made by Sociéte de Véhicules Electriques, will go on sale in France this year

— It comes as a utility vehicle with two seats or a passenger car with five seats

— It can travel at 80 mph (130 km/h)

— The battery takes 4 to 8 hours to charge

— The first, rudimentary, electric car was designed by Professor Stratingh in the Netherlands in 1835

— The average modern electric car uses about one tonne of batteries to store energy equivalant to seven kilos of petrol

— The UK offers free road tax to cars with very low emissions, and road tax of £30 to £40 for hybrids and alternative fuel vehicles

— Electric cars are exempt from the London Congestion Charge

— There are 20 public recharge points across Britain for electric cars

Sources: www.clean-auto.com; www.mygreenwheels.com; www.energysaving trust.org.uk; www.travelsmart.gov.au