Prosecutors in Paris yesterday said they had opened an investigation into "serious fraud" against the embattled German carmaker on February 19, assigning three magistrates to head it.
The probe follows a preliminary inquiry that started in early October. Serious fraud office chief Nathalie Homobono said investigators had already established that Volkswagen had cheated "with intent".

At the same time, German prosecutors said the number of suspects under their own investigation had increased from six to 17, but that no former or current board members are involved.

VW, which until recently had ambitions to become the world's biggest carmaker, is battling to resolve its deepest- ever crisis sparked by revelations that it installed emissions-cheating software into 11 million diesel engines worldwide.
The software, known as a "defeat device", limits the output of toxic nitrogen oxides to US legal limits during emissions test by regulators. But when the vehicles are in actual use, the software allows them to spew poisonous gases at up to 40 times the permitted levels. Nitrogen oxide is a pollutant associated with respiratory problems and defeat devices are prohibited in the United States, where the VW scam was originally exposed, as well as in other countries.