A French judge put detained Russian businessman and lawmaker Suleiman Kerimov under formal investigation for suspected tax evasion and set strict conditions on his release late on November 22.
Prosecutors said bail was set at 5 million euros and Kerimov must hand in his passport and agree to remain in the Nice area of France, where he was arrested on November 20 at the Cote D'Azur International Airport near the French Riviera.
The arrest prompted outrage in Russia and the Kremlin has vowed to defend Kerimov. The Russian Foreign Ministry said on November 22 that it had summoned the charge d'affaires of the French Embassy in Moscow to protest the arrest.
France's formal investigation of Kerimov, 51, is a step that often, but not always, leads to a trial under the French legal system. Prosecutors said it was opened on suspicion of aggravated laundering of tax fraud proceeds, a crime that carries a prison sentence of up to 10 years.
A French judicial source told Reuters that the investigation centers on Kerimov's purchase of several luxury residences on the French Riviera via shell companies, something that could have enabled him to reduce taxes owed to the French state.
The Kremlin earlier pledged its support for Kerimov, whose fortune is estimated at $6.3 billion by Forbes magazine.
"The senator status and the fact that he is a Russian citizen is a guarantee that we will, of course, put in all possible efforts to defend his lawful interests," Kremlin spokesman Dmitry Peskov said on November 22.
Kerimov represents the southern region of Dagestan in Russia's upper house of parliament, known as the Federal Council, and the Russian Foreign Ministry said earlier that it had notified France that he has diplomatic immunity.
Russia's state-run RIA Novosti news agency, however, cited an unidentified Federation Council source as saying that Kerimov had not traveled to France using his diplomatic passport because he was not there on official business.
A spokeswoman for the French Foreign Ministry said Kerimov could only claim immunity in relation to his work as a lawmaker.
"It is for the relevant judge to decide whether the reasons for his prosecution relate to his job and therefore whether he is protected by immunity," she said.
Much of Kerimov's fortune comes from controlling Russia's largest gold producer Polyus, though he has also held shares in potash giant Uralkali and construction company PIK Group.
With reporting by AFP, Reuters, AP, TASS, Interfax, dpa, and RIA-Novosti