Renault's entire senior management team is implicated in an investigation into emissions test cheating, news agency Agence France-Presse has reported.
The agency says documents it has obtained show that the "entire chain of management", including chairman and chief executive Carlos Ghosn, were involved in the suspected fraud.
The document reportedly shows investigators believe suspicious practices may have been in place since as far back as 1990.
Earlier on Wednesday Renault denied reports that its vehicles are equipped with software that allowed them to appear less polluting in tests than they are in the road
The statement followed a report in French newspaper Liberation, which claimed to have obtained an investigative document from the Economy Ministry indicating that emissions from two models – the Renault Captur and the Clio IV – spewed emissions more than 300 per cent higher than the legal limit in real-life conditions.
The ministry's fraud department handed its findings to prosecutors in November.
Renault recalled 15,000 cars last year over excessive levels of harmful gases, but the company insisted there was no intentional wrongdoing.
Volkswagen has already agreed to pay more than $19bn in US fines over the scandal.
In January, Fiat Chrysler was also accused by US regulators of cheating the tests. The company could face a fine of up to $4.6bn.
Additional reporting by AP
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