Former International Monetary Fund boss Dominique Strauss-Kahn has been placed under formal investigation in France over alleged involvement in a prostitution ring.
The move could lead to formal charges.
He has admitted attending parties where the authorities believe prostitutes were provided by a gang, but denies knowing that they were prostitutes.
Mr Strauss-Kahn faces preliminary charges of procuring prostitutes and involvement in an "organised gang", one of his lawyers said.
The 62-year-old former IMF head, who could face up to 20 years in prison if tried and convicted, was released on 100,000 euros ($135,000) bail.
Prosecutors say Mr Strauss-Kahn cannot contact defendants, plaintiffs, witnesses or the media in relation to the case.
The BBC's Christian Fraser in Paris says the allegations relate to his supposed involvement in a vice ring that hired prostitutes for hotel orgies, mainly in Lille, but also in Paris and Washington.
The case has become known in France as the "Carlton affair", named after a hotel where several orgies are said to have been held.
The magistrates are examining allegations that business associates of Mr Strauss-Kahn were involved in the prostitution ring, and misusing corporate funds.
Eight people have already been placed under formal investigation, including a senior police officer.
BBC News - Dominique Strauss-Kahn on formal sex ring investigation
The move could lead to formal charges.
He has admitted attending parties where the authorities believe prostitutes were provided by a gang, but denies knowing that they were prostitutes.
Mr Strauss-Kahn faces preliminary charges of procuring prostitutes and involvement in an "organised gang", one of his lawyers said.
The 62-year-old former IMF head, who could face up to 20 years in prison if tried and convicted, was released on 100,000 euros ($135,000) bail.
Prosecutors say Mr Strauss-Kahn cannot contact defendants, plaintiffs, witnesses or the media in relation to the case.
The BBC's Christian Fraser in Paris says the allegations relate to his supposed involvement in a vice ring that hired prostitutes for hotel orgies, mainly in Lille, but also in Paris and Washington.
The case has become known in France as the "Carlton affair", named after a hotel where several orgies are said to have been held.
The magistrates are examining allegations that business associates of Mr Strauss-Kahn were involved in the prostitution ring, and misusing corporate funds.
Eight people have already been placed under formal investigation, including a senior police officer.
BBC News - Dominique Strauss-Kahn on formal sex ring investigation
