Former IMF chief and one-time French presidential hopeful Dominique Strauss-Kahn on Monday told a Lille court that he had taken part in only a dozen sex parties and that he did not know the women present at the events were prostitutes, the BBC reported.

Prosecutors say the Socialist politician helped procure sex workers for a prostitution ring based at a hotel in northern France, the British channel detailed. They have been quoted as saying that the 65-year-old played a key role in facilitating the orgies, describing him as the "party king."

Strauss-Kahn stepped down from his position as director of the International Monetary Fund in 2011 after a New York hotel maid accused him of sexual assault. The criminal case was eventually dismissed when the hotel employee's credibility came under scrutiny, CNN recalled, but still resulted in months of legal battle.

In France, where he is charged with "procuring with aggravating circumstances," the issues of whether Strauss-Kahn knew that the women were sex workers and of who organized the parties are central to the three-week trial, Reuters explained. While prostitution itself is not illegal in France, supplying prostitutes is, the BBC noted.

On his way to the Lille courthouse, Strauss-Kahn's car was delayed when three topless protesters from the FEMEN group threw themselves on the vehicle, according to Reuters. During the trial, meanwhile, Strauss-Kahn thought to downplay the frequency of the parties and described them as casual meetings between like-minded people.

"When you read the criminal complaint you get the impression it was this frenetic activity," the man once considered a frontrunner in France's 2012 presidential elections said. "But it was four times a year -- not more than that. It wasn't this out-of-control activity that the complaint suggests."

Though he has admitted of taking part in what he calls "licentious evenings," Strauss-Kahn insisted that he was not guilty of the offenses he is charged with, according to the BBC.

"I committed no crime, no offense," he said when he took the stand on Tuesday.

One ex-prostitute hired for one of the sex parties in Paris, however, insisted that it was different from other gatherings, Reuters detailed.

"I found myself in the middle of all these girls around this man," she said with reference to Strauss-Kahn. "There weren't other men, so it wasn't a libertine gathering -- at least my definition."