Dominique Strauss-Kahn's arrest in Lille, northern France, by police investigating a vice ring has put the controversial former head of the IMF back in the spotlight.

Strauss-Kahn, who resigned as boss of the International Monetary Fund in May over sexual assault allegations, was being held for questioning as part of a corruption probe into alleged orgies with prostitutes in Paris and Washington.

He will be interrogated over allegations that he aided the procurement of prostitutes and benefited from fraud.

Under French law police can question him for 48 hours before he is placed under formal investigation - the equivalent of being charged. He previously denied any wrongdoing.

Using prostitutes is not illegal in France but investigators suspect that the prostitutes with whom Strauss-Khan allegedly had sex were paid for using company funds.

The "Affair Carlton" began with an investigation into a notorious Belgian pimp and and alleged llinks to executives at the luxurious Hotel Carlton in Lille.

After suspicions were raised that the hotel was used by a high-class vice ring, claims surfaced that some prostitutes were also taken to Washington DC and Paris, where they met influential clients at other luxury hotels. These included the Murano Hotel in Paris and the W Hotel in Washington DC, both of which have four stars.