PARIS (AFP) - The pimping case against Dominique Strauss-Kahn has "collapsed", a lawyer for the former IMF chief said Wednesday, summing up a trial which has exposed the most intimate details of his client's sex life.

The 65-year-old Strauss-Kahn, once seen as a frontrunner for the French presidency, is on trial in the northern city of Lille, charged with procuring prostitutes to attend sex parties in Brussels, Paris and Washington.

But his lawyers, delivering their closing arguments, said the law had been "twisted" to try and attack Strauss-Kahn over his morals in a case which honed in on his sexual proclivities. A date for the verdict will be announced on Friday.

Strauss-Kahn received a boost during the week after two former prostitutes dropped a civil lawsuit against him, and the prosecutor called for him to be acquitted for lack of evidence.

The silver-haired economist has maintained he never knew the women brought by his entourage to the orgies were prostitutes. The friends in question testified they had kept the fact secret from him.

While prostitution is legal in France, organising and profiting from prostitution is considered pimping and is punishable by up to 10 years in prison.

The court tried to prove that Strauss-Kahn had played a role in organising for prostitutes to attend the sex parties, in text messages in which he referred to women as "equipment".

"Who do you have in your baggage?" he asked his friend and co-accused Fabrice Paszkowski in one message. But Strauss-Kahn brushed these comments off as "barracks talk". His insistence that he didn't know the women were prostitutes also quashed the argument that the use of his "bachelor pad" in Paris to host the sex parties constituted pimping.

"What we were expecting has happened: This case has collapsed," Strauss-Kahn's veteran lawyer Henri Leclerc, 84, told the court.

"Everything that is not forbidden by the law cannot be prevented," he said, quoting from a key French revolution document, The Declaration of the Rights of Man and Citizen of 1789, to slam the court's focus on Strauss-Kahn's morals.

"The law, the law! As for morals, each to their own. Virtue is practised, not commented upon," he said, with Strauss-Kahn paying close attention from the dock.

"You have heard the arguments, there is nothing left ... of a case which has cost a fortune," said Leclerc.

The former prostitutes who testified against Strauss-Kahn were pressed to recount lurid details of how he sodomised them, and describe wild scenes of group sex, which pushed Strauss-Kahn to angrily retort that he was not on trial for "deviant acts".

He has admitted he is a libertine, but said he is "horrified" by the use of prostitutes.