The 65-year-old former Nissan boss was served a fourth arrest warrant on April 4, less than a month after being released on bail following 108 days in detention.
Ghosn's defence team has launched a public and fierce battle against Tokyo prosecutors, calling the latest arrest "illegal" in documents seen by Reuters.
New Renault Chairman Jean-Dominique Senard told managers they had proved their ability to "overcome our differences and keep the alliance strong", also invoking a need for quality improvements and swift joint decision-making, sources said. The scandal also remains a troubling distraction.
In this case with many twists, the wife of Carlos Ghosn, Carole, was heard as a witness Thursday. Formal charges involving those allegations have not been filed.
His lawyers immediately appealed the decision but the Tokyo District Court rejected the appeal.
They question him on suspicion of misappropriation of funds from Nissan, made via a distributor of vehicles of the manufacturer overseas.
Officials arrested Ghosn on suspicion of enriching himself at a cost of $5 million to Nissan, having already charged him for financial misbehavior.
Ghosn, who led the Japanese carmaker for two decades, says he is innocent.
NHK has learned the details of email exchanges that indicate funds from Nissan Motor had been channeled to dummy companies effectively owned by former Nissan Motor chairman Carlos Ghosn.
In a video message released Tuesday, Ghosn said his arrest was the result of "backstabbing" by Nissan, saying that a "few executives" there felt threatened by what might happen to the company's autonomy in a potential convergence or merger with Renault.