France has opened a formal investigation into suspected "aggravated fraud" by Volkswagen following revelations the German carmaker rigged vehicle diesel emissions tests, the Paris prosecutor's office said on Tuesday.
The prosecutor had already opened a preliminary inquiry in October, and French police had carried out searches at the German carmaker's offices in France, seizing computer material.
Volkswagen has said 946,092 vehicles in France were equipped with the EA 189 engines potentially affected by the emissions data manipulation carried out by the company worldwide.
The probe concerns vehicles sold in France, according to the prosecutor's office.
Meanwhile on Tuesday, German insurer Allianz plans to sue Volkswagen in the coming weeks to seek compensation for a severe drop in the car maker's share price stemming from the "Dieselgate" emissions scandal, a source familiar with the situation said.
The planned lawsuit by Allianz Global Investors (AGI) represents the first such action by a major German institution against the national carmaking icon, which is still reeling from the biggest corporate scandal in its history.
"It will happen within this month," the person said.