An appeal court in southern France ordered billionaire Russian businessman and senator Suleyman Kerimov to post bail of 40 million euros ($47 million) on Wednesday pending a tax fraud investigation.

Kerimov was arrested in late November in the city of Nice over suspected tax evasion related to the purchase of luxury properties on the French Riviera, provoking an angry reaction from the Russian government.

He posted bail of five million euros and handed over his passport after he was charged with tax fraud on November 23, but prosecutors lodged an appeal for a heftier bail. 

Nice prosecutor Jean-Michel Pretre said Monday that between 500 million and 750 million euros in "secret money" was at stake.