A lawyer for Dominique Strauss-Kahn has predicted a French pimping case against him will collapse and said a libertine lifestyle was not a crime.
Henri Leclerc told reporters that evidence against Strauss-Kahn was “hollow” after the former IMF chief was formally placed under investigation.
Strauss-Kahn admits attending sex parties but denies he knew that prostitutes were there.
Allies in the French Socialist Party have distanced themselves from him.
Strauss-Kahn, 62, was released on bail of 100,000 euros (£84,000; $135,000) after questioning in the northern city of Lille.
He faces up to 20 years in prison if tried and convicted.
Last May, he resigned from the IMF after being accused of attempting to rape hotel maid Nafissatou Diallo in New York. Those charges were later dropped.
 Diallo, 32, is now bringing a civil case against him, which is due to start in New York on Wednesday. He has always denied any wrongdoing.
Strauss-Kahn faces allegations of 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 Lille hotel where several orgies are said to have been held.
Magistrates are examining allegations that business associates of Strauss-Kahn were involved in the prostitution ring, misusing corporate funds.
Eight people have already been placed under formal investigation, including a senior police officer. (BBC)
