The carmaker replaced Ghosn as chairman and chief executive on January 24, more than two months after his arrest in Japan over allegations of financial misconduct at Nissan, Renault's 43.4 percent-owned affiliate.
French newspaper Le Figaro reported that Versailles allowed Ghosn to host his lavish 2016 Marie Antoinette-themed wedding reception on its grounds in exchange for Renault's donations to the chateau, resplendent home to France's last kings.
In a statement, the French auto manufacturer says that after compliance audits were initiated on November 23, 2018, it discovered that a €50,000 contribution was allocated to Ghosn's personal benefit as a charitable donation with the Château de Versailles where his wedding was held.
French carmaker Renault needs to show "total transparency" as it probes its business practices, including a sponsorship deal stuck with the Chateau de Versailles, finance minister Bruno Le Maire said on Thursday.
"Renault has chose to bring these findings to the attention of the judicial authorities".
Ghosn led both Renault and Nissan and championed their alliance as it grew into the world's biggest-selling automaker.
Its findings stem from an internal probe Renault started in November shortly after Ghosn was arrested in Tokyo.
'I am accused of under-reporting income I never received! It's obvious: it's a story of betrayal.
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.
But facing the prospect of several more months behind bars before his trial opens, Ghosn last month relinquished his grip as CEO of Renault.
Ghosn was the linchpin of the three-way alliance, earning industry plaudits for driving together a sometimes fractious threesome with headquarters 10,000 kilometres apart.
Adding to the complexity, the French state owns just over 15 percent of Renault, and government officials have said they are keeping a close eye on the alliance's future.
Renault holds a 43-percent stake in Nissan along with voting rights, while the latter owns only a 15-percent non-voting stake in the former.