Strauss-Kahn: Why is ex-IMF chief on trial for pimping? Published duration 10 February 2015

image copyright AP image caption Dominique Strauss-Kahn says he committed no crime and no offence

The former head of the International Monetary Fund, Dominique Strauss-Kahn, has told a French court that he attended orgies, but would never have done so if he had known they involved prostitutes.

He is accused of "aggravated pimping", or helping to procure sex workers for a prostitution ring based at a hotel in Lille. Thirteen other people are on trial with him.

DSK, as he is widely known in France, was once seen as a leading contender for the French presidency, but if found guilty he could end up in jail.

What is the trial about?

The "Carlton affair" - named after the hotel in the northern French city of Lille that sparked the initial investigation - erupted in 2011. An anonymous tip-off alerted officials that the hotel was being used for prostitution.

Further investigation uncovered an international prostitution ring involving prominent local businessmen.

It emerged that some of the suspects had close links to Mr Strauss-Kahn and that he took part in sex parties organised by them in France and Washington in late 2010 and early 2011. Prostitutes have said they were paid to attend those parties.

Who are his co-defendants?

image copyright Reuters image caption Dominique Alderweireld is the owner of several brothels

The 13 other people also facing the charge of "aggravated pimping" include:

Dominique Alderweireld, nicknamed "Dodo la Saumure" ("Dodo the pimp" or, more accurately, "fishy Dodo"), a French national who owns several brothels in Belgium near the French border

image copyright AFP/Reuters image caption David Roquet (L), Jean-Christophe Lagarde (C) Rene Kojfer (R)

David Roquet, a former executive for a construction firm based in northern France; he has admitted to paying prostitutes to attend sex parties. He told the court that such parties were important for his company as they enabled him to have contact with Mr Strauss-Kahn, a man widely seen as the front-runner for the 2012 presidency

Jean-Christophe Lagarde, a former police commissioner, accused of organising sex parties, again to secure influence with DSK. He denies knowing the women were prostitutes

Rene Kojfer, former Carlton Hotel publicist, alleged to have arranged sex parties in Lille with Dominique Alderweireld. He denies pimping, saying he simply introduced friends to prostitutes that he knew

image copyright AFP image caption Fabrice Paszkowski (L), Virginie Dufour (C) and Emmanuel Riglaire (R)

Fabrice Paszkowski, another businessman and alleged organiser, described by Mr Strauss-Kahn as a "friend". He told the court that he and David Roquet had concealed from Mr Strauss-Kahn the fact that prostitutes had been hired

Virginie Dufour, previously married to Mr Paszkowski and accused of helping to organise the sex parties

Emmanuel Riglaire, a high profile lawyer in Lille accused of introducing one of the prostitutes, Mounia, to David Roquet. Mr Riglaire denies the charges

What is DSK accused of?

Using prostitutes is legal in France.

However under article 225-5 of the criminal code, the definition of pimping includes not just procuring, but also facilitating prostitution "in any way".

Investigators, who have found SMS (text) messages between Mr Strauss-Kahn and the other co-defendants, believe that the sex parties were organised specifically for the benefit of the former head of the International Monetary Fund.

Prosecutors therefore believe he played a major role in instigating the orgies. Some have described him as the "party king".

He and his co-accused are accused of "aggravated" pimping because the prostitution activities were allegedly organised by a group of people.

If convicted he could face a 10-year prison sentence and a fine of €1.5m (£1.13m; $1.72 million).

What do we know about the prostitutes?

image copyright AFP image caption A court sketch of Jade, a Belgian ex-prostitute who said she was introduced to a "public figure"

Two former prostitutes have agreed to help the prosecution, Mounia and Jade, and both believe he must have known they were prostitutes. Both attended sex parties at the Hotel Murano in Paris between 2009 and 2010, but never together.

Mounia told the court that she was chosen especially for Dominique Strauss-Kahn, but acknowledged no mention of money was ever raised in his presence. She said she was paid €900 (£690) by David Roquet, for what she had been told would be a "small party".

She also says DSK forced her to commit an act "against nature" at a party in Paris, which he denies.

Jade worked for brothel owner Dominique Alderweireld and had attended lunchtime sex parties in Lille. She is also believed to have travelled to Washington to take part in a sex party there. In her testimony, she said she had been introduced to a "public figure", and said she was paid either by Dominique Alderweireld or Rene Kojfer.

What is DSK's defence?

image copyright AFP image caption Mr Strauss-Kahn told the court that orgies were rare

Mr Strauss-Kahn has never denied taking part in sex parties. But, he insists: "I committed no crime, no offence."

His main line of defence is that he had no idea some of the women there were prostitutes. One of his lawyers once said: "I challenge you to tell a naked prostitute from a naked society lady."

Giving evidence on 10 February, he also accused prosecutors of having greatly exaggerated the frequency of his "licentious evenings". He said: "There were only 12 parties in total - that is four per year over three years."

It was the prostitutes who said it was obvious what they were, he told the court. "But many other witnesses say they didn't see any prostitutes. I maintain that I neither knew nor suspected there were prostitutes."