Disgraced ex-IMF chief Dominique Strauss-Kahn and his heiress wife are suing a top aide of French President Nicolas Sarkozy and several papers for invasion of their privacy, their lawyers say.
Strauss-Kahn and Anne Sinclair want 100,000 euros ($181,000 NZD) from Le Figaro over a story speculating Sinclair was upset by reports her husband had sex parties with prostitutes, according to a writ served on the daily.
The paper also speculated that Sinclair, a celebrity television journalist and the heiress to an art fortune, might separate from her husband.
The writ, seen by AFP, said that if the case was successful, the money was to be donated to the anti-poverty charity Secours Populaire.
Similar writs will be served in the coming days to the weekly magazines L'Express, Nouvel Observateur, Paris Match and VSD, lawyer Richard Malka told AFP.
Recent articles in the French press have speculated that Strauss-Kahn was close to a nervous breakdown and had admitted to his entourage that he needed treatment for his compulsive sexual behaviour.
The couple are also planning to press charges against Sarkozy aide Henri Guaino over a television interview in which he said that in the Strauss-Kahn affair "one is in a zone where private life meets criminality", Malka said.
Strauss-Kahn, a 62-year-old Socialist politician and former presidential hopeful, resigned from the International Monetary Fund in May after he was arrested and accused of attempting to rape a New York hotel maid.
The US case against him eventually collapsed, but he has been dogged by scandal since returning to France.
Strauss-Kahn's name has been linked to a judicial investigation into an illegal prostitution ring operating out of luxury hotels in the northern French city of Lille and a string of Belgian brothels.
Press reports based on leaks from the investigation have said prostitutes from the Lille network were taken to Paris and Washington to entertain the then IMF director at orgies in restaurants and five star hotels.
French media have revealed text messages allegedly sent by Strauss-Kahn to a businessman detained on suspicion of organising sex parties in restaurants and swingers clubs in Paris, Washington, Madrid, Vienna and Ghent, Belgium.
Strauss-Kahn has demanded to be questioned by the judges leading the inquiry, hoping to halt what his lawyers brand a "media lynching", but some warn he could face charges if the case expands to cover alleged graft or influence peddling.
Magistrates have already charged several leading local figures with organising the ring and there are suspicions that a construction company executive used his firm's money to entertain guests at sex parties.
Strauss-Kahn was once courted by dozens of senior figures, keen for a role in his expected future government, or hoping some of the glamour and energy of his jet-setting lifestyle and celebrity marriage would rub off.
Even after the shock of the US case - which collapsed after prosecutors came to doubt the testimony of the alleged victim but ended his IMF career - many stood by him, predicting an improbable comeback for their champion.
But now, with each week bringing new unseemly allegations, the small court of hangers-on who used to meet or telephone their champion at his elegant flat in Paris's super-fashionable Place des Vosges has dispersed.