A French court has acquitted Dominique Strauss-Kahn, the former International Monetary Fund (IMF) chief, of aggravated pimping charges.

The 66-year-old nodded his head in court in Lille on Friday in acknowledgement of the verdict which found him not guilty of procuring prostitutes to take part in sex parties in Paris, Brussels and Washington.

Al Jazeera's Barnaby Phillips, reporting from London, said the outcome was in line with what most observers had expected.

"The prosecution had a hard time proving that [Strauss-Kahn] organised these sex parties," he said.

Inside Story: DSK - The case and the chaos

Strauss-Kahn saw his career at the head of the IMF - and his French presidential prospects - unravel when a New York hotel maid accused him of sexual assault in 2011.

Not long after those criminal charges were dropped and the case settled in a civil suit, his name cropped up in a probe into a prostitution ring in northern France, which provided sex workers for orgies he attended.

He was charged with "aggravated pimping" for allegedly aiding and abetting the prostitution of seven women - a charge punishable by up to 10 years in prison.

However, even the prosecutor called for him to be acquitted, saying that "neither the judicial enquiry nor the hearing have established that Mr Strauss-Kahn is guilty".

"All that for this?" Strauss-Kahn said as he rose to leave the courtroom with his girlfriend and adult daughter.

"What a waste," he added, according to the Associated Press news agency.

In often sordid testimony, the women involved in the sex parties described sometimes-brutal nights that, they said, were not fun for them at all.

The panel of judges ruled that Strauss-Kahn, whose political career was tarnished by the allegations, was not involved in hiring the women or paying them.

The former IMF chief was among more than a dozen defendants, including hotel managers, entrepreneurs, a lawyer and a police chief. They were accused of participating in or organising the collective sexual encounters in Paris, Washington and in the Brussels region between 2008 and 2011, when Strauss-Kahn was at the IMF and married.

Only one, a hotel manager, was convicted in the pimping case.

During the three-week trial in February, the man known in France as DSK never wavered in his insistence that he did not know that the young women at the parties were prostitutes. He said he thought they were simply "libertine."

Source: Al Jazeera and agencies