VW's French unit reported false delivery figures since 2010

The auditors found a number of cars were registered by their owners "several months or even years" after the deliveries were recorded by the French business - a process that normally takes weeks - and that some of the vehicles classed as delivered didn't even have purchase contracts, the magazine said.

It said inaccurate information was provided on almost 800,000 vehicles in total.

A spokesman at Volkswagen's Wolfsburg-based headquarters declined to discuss the article, saying the company "doesn't comment on internal documents." The French division's actions started in 2010 and affected cars from VW's namesake brand, luxury division Audi, Czech unit Skoda and the Spanish Seat brand, Der Spiegel said.

VW group chief executive Matthias Mueller was given the auditors' report on April 24 and as a result, the head of VW's French operations, Jacques Rivoal, quit, the magazine said. Rivoal couldn't be reached for comment by Reuters on Friday. When Rivoal's departure was announced in May, VW said "strategic differences" with management had caused the French manager's exit, without being more specific.