Former IMF head Dominique Strauss-Kahn will face trial on pimping charges along with 12 others in connection with an alleged prostitution ring at a Lille hotel, the local prosecutors' office said.

Investigation judges had determined on Friday that Strauss-Kahn should be judged by a criminal court in the case involving sex parties which he has acknowledged attending.

Prosecutors had in June called for the charges of "aggravated pimping as part of an organised gang" against Strauss-Kahn, 64, who has been under investigation in the case since 2012, to be dropped, but investigating magistrates have decided he should face trial.

"We are not in the realm of the law, we're in ideology. We are sending someone to court for nothing," Henri Leclerc, one of Strauss-Kahn's lawyers told the Reuters news agency.

'Aggravated pimping'

Pimping under French law is a broad crime that can encompass aiding or encouraging the act of prostitution.

Strauss-Kahn was charged with the more serious form because it allegedly involved more than one prostitute.

The crime carries a maximum term of 10 years in prison and a fine of $2ml.

The so-called Carlton affair, named after a hotel in Lille, involves sex parties which Strauss-Kahn says he was unaware that the women who participated were prostitutes.

The former French finance minister quit his post as head of the International Monetary Fund in 2011 after being accused of raping a maid in New York, a charge that was later dropped.

Source: Agencies