Paris (CNN) -- Police in France on Tuesday were questioning former International Monetary Fund chief Dominique Strauss-Kahn as they investigated an alleged prostitution ring that may have operated out of two French hotels.
Strauss-Kahn has been urging authorities since September to question him over his alleged involvement in the ring, saying it would help clear his name.
His attorneys released a statement in November saying Strauss-Kahn wanted to address the so-called "media lynching" that he says falsely links him to sex parties with prostitutes in Europe and the United States.
The attorneys' statement called the allegations against Strauss-Kahn "unhealthy, sensationalist and not without a political agenda."
Strauss-Kahn attorney Henri Le Clerc acknowledged in an interview with radio station Europe1 in December that his client attended such sex parties, but said Strauss-Kahn was unaware the women in attendance were prostitutes.
"I challenge you to distinguish a naked prostitute from a 'woman of the world' who is naked," he told the station.
Another lawyer, Frederique Beaulieu, accompanied Strauss-Kahn to the police station in Lille Tuesday, but did not make any comment, a police spokesman in the northern French city said.
The questioning was going on behind closed doors, and was extended Tuesday night for another 24 hours by the magistrate police.
His lawyers in Paris could not be reached for comment Tuesday because they had traveled to Lille.
Strauss-Kahn has been linked with a number of sex scandals in the past year -- one of which torpedoed his expected plan to run for the French presidency this year -- but he has not been convicted of any crime.
He stepped down from the top job at the IMF after a New York hotel maid accused him of sexual assault and attempted rape in May.
The case ultimately fell apart after the alleged victim posed significant credibility issues for prosecutors, despite forensic evidence that showed a sexual encounter had occurred.
The prostitution probe, nicknamed the "Carlton Affair" by the French press, kicked off in October.
It centers around the city of Lille, where investigators began looking into claims that luxury hotels, including the Carlton, served as a base for a high-profile prostitution network.
While prostitution is not illegal in France, profiting from profiting from the prostitution of another person is against the law, according to the French Penal Code. Authorities are also investigating whether corporate funds were used to pay for the prostitutes. In the December Europe1 interview, Le Clerc said there is no evidence that such funds were misappropriated.
A hotel manager and four other men were arrested late last year in connection with the investigation.
Strauss-Kahn has not been arrested or charged in connection with the Carlton Affair, but the incident continues a string of sexual allegations against him.
He also faced allegations of attempted rape from a young French writer. Tristane Banon filed a complaint, alleging a 2003 attack, though it could not be pursued because of a statute of limitations.
Strauss-Kahn denied the allegations and has since filed a countersuit in France, alleging slander.
CNN's Saskya Vandoorne, Anna Prichard and Niki Cook contributed to this report.