PARIS - French court on Tuesday dropped charges accusing ex-IMF chief Dominique Strauss-Kahn of gang rape in late 2010 in Washington, the United States, local media reported.

Prosecutor of Lille court, in northern France, decided to take no further investigation into alleged gang rape involving Strauss-Kahn due to insufficient evidence after a witness withdrew her statement, the report said.

In May, Lille court opened a probe to investigate on an incident "that could be described as gang rape" in which Strauss-Kahn could have forced sex with a prostitute with the help of his friends.

The scandal-hit former French finance minister had already been questioned over his alleged involvement in an illegal prostitution ring which supplied women to clients in the city's luxury Carlton hotel and for abuse of corporate funds.

Being on fire of a judicial investigation over charges of sexual assault and attempted rape on a hotel maid in New York last year, Strauss-Kahn was forced to quit the IMF and to keep a distance to France's political life.