He is not allowed to have contact with other people involved in the investigation, nor is he permitted to talk to the media about the case. Strauss-Kahn was released under a 100,000-euro bail, according to prosecutors.
Earlier in the day, he was questioned by a judge about his alleged involvement in the ring. The meeting was initially scheduled for Wednesday.
A spokesperson for the judge told CNN it was the judge’s decision to change the date, but did not say why the decision was made.
The charge alleges involvement in the habitual operation of a prostitution racket. Specifically, “aggravated’ means on a regular and involved basis, and “pimping” means actually facilitating a prostitution operation, not just being a customer.
Last month, Strauss-Kahn was held for more than 24 hours by police in Lille and questioned about his alleged involvement in the prostitution ring.
His attorneys released a statement in November calling the allegations against their client “unhealthy, sensationalist and not without a political agenda.”
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.
In December, Strauss-Kahn’s attorney, Henri Leclerc, acknowledged in an interview with radio station Europe1 that his client attended sex parties, but said Strauss-Kahn was unaware the women in attendance were prostitutes.
While prostitution is not illegal in France, 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, Leclerc 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.
The Carlton Affair continues a string of sexual allegations against Strauss-Kahn.
The former IMF chief 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. 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.
Strauss-Kahn 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.