“Jade,” a now-retired prostitute, told the court in the northern city of Lille how the Carlton vice ring had introduced her to “a public figure”, making an apparent reference to Strauss-Kahn, who was once one of the most powerful men in the world.
Witnesses are not allowed to refer to those who are not present and Strauss-Kahn is not due to appear in court until he testifies next week.
The judge asked Jade directly what she was paid for: "Well, I wasn't there doing the cleaning", she retorted.
"There were sexual relations but each person had a partner, there was no orgy where everyone gets involved, the men made their choice," she said, describing a "classy" environment with champagne and a buffet.
The first part of the multi-faceted trial, with a total of 14 accused, is focused on a prostitution ring allegedly run by the owners and a publicist for the luxury Carlton hotel in the northern city of Lille.
It was during a probe into the so-called "Carlton Affair" that investigators stumbled across the name of Strauss-Kahn, whose high-flying career and presidential prospects imploded when a New York hotel maid accused him of sexual assault in 2011.
Members of Strauss-Kahn's entourage are accused of procuring prostitutes from René Kojfer, 74, a former public relations manager for the Carlton and Jade's employer Dominique Alderweireld, a notorious brothel owner in Belgium, who is known as "Dodo the Pimp".
Strauss-Kahn said Monday he had never set foot in the Carlton and did not know Kojfer or "Dodo".
Kojfer on Tuesday denied the charge of "aggravated pimping" of eight women, saying he was merely doing a service for his friends by introducing them to the prostitutes.
The trial was suspended early after Kojfer, who has heart problems, said he did not feel well.
Lunchtime sex parties
Jade, bespectacled and with a brunette bob, dressed in neutral colours with a scarf wrapped tightly around her neck, is expected to tell the trial about the sex parties she attended with DSK, including one in Washington, according to prosecution sources.
She burst into tears several times as she told how she had - of her own volition - taken up prostitution to support her two young children after her divorce.
She explained Kojfer and Dodo would organise for her and other women to attend lunchtime sex parties at a private Lille apartment.
According to prosecution sources, Jade had spoken of full-on orgies during the investigation leading up to the case, describing them as "carnage with a heap of mattresses on the floor".
In the courtroom, however, she said there were no orgies, but that the men selected a woman each.
Prostitution is legal in France but procuring - the legal term for pimping which includes encouraging, benefiting from or organising prostitution - is a crime.
As such the trial focused on who paid whom, and who gave the orders.
On one occasion, Jade said Kojfer - accused of setting up local businessmen and police officials with prostitutes - handed her cash directly, and in other cases the bill was settled by "Dodo".
She claimed Kojfer paid the girls much less than promised, saying "times are hard", adding "but we got a free bathrobe."
Another ex-prostitute "Sonia" told the court how she provided free sexual favours to Kojfer "because he introduced me to his friends".
Self-confessed 'libertine'
The trial is the latest in a series of cases offering a peek behind the bedroom door of a man once tipped as a potential challenger to former French president Nicolas Sarkozy.
France was stunned when it saw Strauss-Kahn paraded handcuffed in front of the world's cameras after a New York hotel maid accused him of sexual assault in May 2011 - a case that was eventually settled in a civil suit.
Strauss-Kahn admits to being a "libertine" who took part in orgies, but denies knowing that the women at the parties were prostitutes.
The economist nonetheless finds himself facing 10 years in prison and a fine of up to 1.5 million euros for "aggravated pimping in an organised group", with investigating judges arguing he played a role in initiating the sex parties and organising the presence of the prostitutes.
(FRANCE 24 with AFP)