72-year-old Bongo, who is the longest-serving political leader in Africa, is believed to have over $4m (£2.8m) in bank accounts held in France.
Mr Cardona had been let go after his son paid more than $580,000 (£400,000) into Mr Bongo's account, the court was told.
In September of last year, a court ruled that the paying of this money to Mr Bongo was against the law and the verdict was upheld despite an appeal on Monday.
Jean-Philippe Le Bail, who is a lawyer for Cardona's son, was quoted by AFP news agency on Thursday as having said: "The accounts held by Omar Bongo in two French banks have been seized."
Rene Cardona had been sent to prison back in 1996 after a business argument with Mr Bongo, who had bought a shipping and fishing firm from him.
