DSK under investigation into underage prostitution at Carlton Hotel in Lille.

One day after DSK escaped from sexual assault charges in France, the former IMF chief has been involved in another investigation into underage prostitution.

Dominique Strauss-Kahn, 62, is among politicians and business leaders allegedly named in a “black book” of guests at Carlton Hotel, in Lille, which was said to double as a brothel.

The judicial inquiry into prostitution at Carlton Hotel was opened in March 2011 amid claims underage girls were involved.

According to French laws, prostitution is legal, but women must be over 18.

As part of the inquiry, Carlton Hotel’s members of senior staff, including the manager and a public relations executive, were arrested at the beginning of this month.

It was reported that members of Carlton Hotel’s staff have acted as “pimps” to their clients, and will face charges of procuring prostitutes, organized conspiracy in criminal acts and money laundering.

According to French Closer magazine, which has published the claims yesterday, the prosecution documents said DSK used prostitutes at the Lille hotel.

“The prostitutes and the go-betweens charging for sex indeed put forward the name of the husband of Anne Sinclair.

“According to one of the girls in the ring, Dominique Strauss-Kahn would have benefitted from her services.”

The magazine, which has a good record for investigative journalism, claimed it has 100% confirmation from Lille examining judges Ausbart and Vignau that DSK was a client of those accused.

DSK would face criminal proceedings if he was found to have paid or slept with an underage girl.

Lille city is just one hour from France capital Paris by high-speed train, and an obvious place for high-profile men to travel to meet prostitutes.

Just one day before the new allegations, on Thursday, judges cleared DSK for attacking French journalist and writer Tristane Banon in 2003, because of the statute of limitations in France, which is three years for sexual assault.

It was the second time in three months DSK has been cleared of sex charges. In August, U.S. prosecutors dropped charges that former IFM chief had raped 32-year-old maid, Nafissatou Diallo, in a Sofitel New York hotel room in May.

DSK still faces civil cases in both Paris and New York over the alleged rape incidents.