Paris-based carmaker PSA Group allegedly used a fraudulent software on almost two million vehicles to manipulate diesel emissions tests, French newspaper Le Monde revealed on Friday.

Volkswagen, Audi, BMW, Porsche and Daimler are under investigation by the EU and German authorities for forming a secret ‘economic cartel’ in the 1990s to collude on diesel emissions, after Daimler blew the whistle, media reported Monday.