Renault said it was alerting French judicial authorities.
Renault said in a statement that "it was identified that a contribution of 50,000 euros, under a sponsorship agreement signed with the Chateau de Versailles, was allocated to Mr. Ghosn's personal benefit".
The French carmaker's disclosure this week that centered around a Marie Antoinette-themed wedding celebration in 2016 was the first time it has publicly flagged a possible impropriety by its jailed former chairman.
Under the terms of the deal, Renault could benefit in return from Versailles access and other services worth a maximum 25 percent of the deal, in this case around 575,000 euros, it said.
In a separate development, Nissan has said that it is also going to include the undeclared remuneration of 9 billion yen ($82 million) to Ghosn in its earnings report next week but that it will also freeze payments to the former executive, The Japan Times says.
"The audit into Renault has started, it is starting to bring out results, I had personally demanded that audit", Le Maire added to reporters at a business event in Paris.
Carlos Ghosn's secretaries are to blame for the "misunderstanding" that led the fallen vehicle executive to hold a wedding reception at the Château de Versailles without paying, his lawyer said today.
It has also exposed rifts between Nissan and French carmaker Renault which, together with Mitsubishi Motors, make up the world's top-selling auto manufacturing group. "Contrary to the accusations made by the prosecutors, I never received any compensation from Nissan that was not disclosed, nor did I ever enter into any binding contract with Nissan to be paid a fixed amount that was not disclosed".
Renault initially stood by Ghosn, but named a new CEO and chairman last month to replace him as his Japanese legal case drags on.
Much of the tension between the partners stems from a complex ownership structure that gives Renault 43 percent of Nissan, whereas Nissan owns just 15 percent stake in the French company - and no voting rights.