Former IMF chief Dominique Strauss-Kahn and his wife Anne Sinclair are to lodge a formal complaint for alleged invasion of privacy following French media reports about them, their lawyers said Monday.

In a statement, Henri Leclerc and Frederique Baulieu slammed "articles showing the most detestable voyeurism about the alleged intentions or frames of mind of Anne Sinclair or of Dominique Strauss-Kahn."

They said there was no public interest to justify a series of leaks, including from a judicial investigation into an alleged prostitution ring linked to Strauss-Kahn and reports that the couple's relationship was in trouble.

French and international media have been closely following one-time French presidential hopeful Strauss-Kahn since he returned to Paris after he was in May accused of attempting to rape a hotel chambermaid in New York.

Strauss-Kahn on Friday demanded that he be questioned by judges investigating the alleged prostitution ring in northern France, claiming he was the victim of a "media lynching".

"Neither judicial nor media necessities authorise anyone not to respect the confidentiality of a judicial investigation, the presumption of innocence and various aspects of private life," the lawyers said Monday.

They accused the media of "fantasising in particular about the alleged intentions or frames of mind of Anne Sinclair or of Dominique Strauss-Kahn under the hypothetical cover of statements by third parties courageously hiding behind anonymity."

"Anne Sinclair and Dominique Strauss-Kahn have given us the most firm instructions to go to court over these excesses," the lawyers said.

"We are already looking at what to do about certain articles showing the most detestable voyeurism and bringing no legitimate news to the general public," the statement said.

The couple will be represented by media lawyer Richard Malka.