Renault will face challenges in the employment courts after it dismissed executives it suspects of leaking company secrets.
Vice-president of advanced engineering Michel Balthazard, his former deputy Bertrand Rochette and deputy head of Renault's electric vehicle programme Matthieu Tenenbaum all deny any wrongdoing but received letters of dismissal at the weekend.
Three executives were suspended on January 5 after Renault said it had found evidence of an organised international network of industrial espionage.
Last Friday Renault lodged a criminal complaint against unnamed people alleging corruption, breaches of trust, theft and concealment.
The Paris prosecutor has opened an official inquiry, which is likely to last several months.