The first part of the multi-faceted trial with 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.
Strauss-Kahn will not appear until he testifies next week, and witnesses are not allowed to refer to those not present, but the now-retired prostitute Jade made references to "a public figure" she met through the "Carlton" vice
It is members of the Carlton ring who allegedly procured prostitutes -- including Jade -- for the entourage of Strauss-Kahn, who threw sex parties for the disgraced former finance minister in Paris, Brussels and Washington.
Jade, bespectacled and with a brunette bob, dressed in neutral colours with a scarf wrapped tightly around her neck, burst into tears several times as she told how she had been forced to take up prostitution to support her two young children after her divorce.
She explained how Rene Kojfer, 74, former public relations manager for the Carlton and her employer Dominique Alderweireld, a notorious brothel owner in Belgium just across the border who is known as "Dodo the Pimp" would organise for her and other women to attend lunchtime sex parties at a private Lille apartment.
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'I wasn't there to clean'
The judge asked her 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.
This is in comparison to the orgies with Strauss-Kahn, which she described during the investigation as "carnage with a heap of mattresses on the floor", according to prosecution sources.
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."
Kojfer denies the charge of "aggravated pimping", saying he was merely doing a service for his friends by introducing them to the prostitutes he knew.