Renault managers linked to espionage claim fight back
Michel Balthazard, the most senior of three sacked Renault executives, has begun legal action to clear his name.
The three were dismissed over allegations of industrial espionage.
His colleague Betrand Rochette has also filed a complaint with French prosecutors, and the third man is said to be preparing legal paperwork.
Mr Balthazard's lawyer Xavier Thouvenin told the BBC a criminal complaint was filed against unnamed individuals to discover who had accused his client.
A second filing was made against Renault for the unfair dismissal of Mr Balthazard.
Mr Balthazard was dismissed last week as head of Renault's long-term development amid reports that secret information about the company's electric car programme had been leaked.
French media reports speculated about money being deposited in Swiss bank accounts and of links with one or more companies in China.
Renault has filed a criminal complaint with the Paris prosecutor's office, alleging it has been the victim of organised industrial espionage, corruption, and breach of trust.
Mr Thouvenin said: "In his letter of employment termination, my client was told of an anonymous claim that he received bribes. Our action is to find who is the whistleblower who has named my client."
He described the claim against Mr Balthazard as "unfounded and slanderous". The other two executives have strongly denied wrongdoing.
French judicial authorities will now decide whether to investigate.
Although media speculation pointed to foreign involvement, Renault has not accused any country or company of being behind the espionage.
Renault and its Japanese partner Nissan have invested $4bn (£2.5bn) to develop electric cars and the two companies are seen to be among the leaders in this field.
Nissan's Leaf electric car was recently launched in the US and Japan.