Environment Minister Segolene Royal said today initial French tests had shown emissions cheating in Volkswagen group vehicles, but cars from other brands were in the clear.

Soon after the Volkswagen admitted in September that some 11 million of its diesel vehicles worldwide were fitted with so-called defeat devices to dupe normal pollution tests, France began a series tests on cars from a number of automakers.

"Of the 10 vehicles of all brands that we've tested so far we've seen that with Volkswagen vehicles there are nitrogen oxide levels five times the legal limit, thus confirming cheating," Royal said on France Info radio.

She said emissions from diesel vehicles from other automakers were also above the legal limit, but still in line with differences to be expected between lab and real-life tests.

The pollution cheating scandal has rocked Volkswagen, wiping nearly 40 per cent off its market capitalisation, forcing its chief executive to resign, and prompting investigations in numerous countries that could result in fines leading to tens of billions of dollars in addition to the nearly 7 billion the carmaker has budgeted to fix the affected vehicles.

Royal said a comprehensive certified testing model would be ready by the end of the month, and be used for checks on around 100 models of vehicles sold in France.