India, Jan. 18 -- Former Nissan boss Carlos Ghosn received nearly eight million euros in "improper payments" from a Netherlands-based joint venture, the Japanese car giant alleged Friday, threatening to sue to recover the funds.

Nissan said Ghosn entered into a personal employment contract with Nissan-Mitsubishi BV (NMBV), a company formed "with the mission of exploring and promoting synergies within the Nissan-Mitsubishi Motors partnership."

"Under that contract, he received a total of 7,822,206.12 euros (including tax) in compensation and other payments of NMBV funds," Nissan said, citing an ongoing investigation into alleged wrongdoing by Ghosn.

The firm said the contract was signed without consultation with current Nissan CEO Hiroto...