Former French oil chief executive Loik Le Floch-Prigent has been charged with being an accessory to fraud in Togo.
Mr Le Floch-Prigent appeared before a judge on Monday evening after being extradited from Ivory Coast.
During a hearing in the court in the capital, Lome, he was questioned for three hours.
The case follows a complaint from Abbas al-Yousef, a businessman from the United Arab Emirates, who alleged that he was victim of a $48m (£30m) fraud.
The BBC's Ebow Godwin in Lome says Mr Le Floch-Prigent looked tired as he was taken into the courtroom at about 18:00 GMT on Monday, refusing to talk to the media.
The 68 year old, who reportedly now works as an oil industry consultant, arrived in Togo over the weekend after his arrest in Ivory Coast on Friday.
Former Togolese Interior Minister Pascal Bodjona has also been charged over the case - he denies any wrongdoing - as well as Togolese businessman Bertin Sow Agba.
According to the AFP news agency, the case involves accusations that a network claimed to have access to $275m in a Togolese account left by former Ivorian military ruler Robert Guei, who was killed in 2002.
Some observers say the case may be politically motivated. Mr Bodjona, who was dropped from cabinet last month, has been an influential member of Togo's ruling party.
Mr Le Floch-Prigent remains in detention. It is not clear when the next hearing will be.
- 24 February