At the next Paris Motor Show, Citroën will launch the “C3 Stop & Start”, which it claims is the first car to be equipped with a system that cuts the engine when the car is stopped and idling, then instantly restarts it at the touch of the accelerator.

Not so, said Volkswagen UK spokesman Mike Orford. Volkswagen offered the diesel Golf 3 Ecomatic in the early 1990s but it was not a success as owners found the motor cutting out when coasting, as well as at junctions disconcerting. The super-economical Lupo 3L TDi diesel model, sold in Germany since 2001, also has a stop-start system, but the coast cut-out was dropped for that following experience with the earlier Golf.

The PSA Peugeot Citroën stop-start system will be combined with the C3’s SensoDrive electronically controlled manual gearbox and a petrol engine so Citroen can rightfully stake claim to a first for petrol-powered cars.

The company claims its “Stop & Start” system is expected to reduce fuel consumption by around 10% for urban driving and by 6% in the standard EU combined cycle.

Stop & Start systems will be gradually offered on other Citroën and Peugeot models, delivering better fuel economy and lower CO2 emissions (which has tax advantages in some European countries, including the UK).

PSA said that trials conducted in a large urban environment have demonstrated that in typical customer use, cars are standing still 30% of the time. This means that, in addition to improved fuel economy and lower CO2 emissions, the urban environment will also benefit from the fact that the cars are completely quiet during the many periods when they are not moving.

Not yet revealed is whether the PSA cars will have a Toyota Prius-like electrically-powered air conditioner compressor to keep the cabin cool when the engine is stopped.