PARIS — French judges have decided not to drop prostitution charges against Dominique Strauss-Kahn. His lawyer says the former International Monetary Fund chief will appeal.

Strauss-Kahn's lawyers have argued the investigating judges in the case are biased. The case revolves around a suspected luxury prostitution ring in northern France.

A court in the French city of Douai decided Wednesday to retain the preliminary charges.

Strauss-Kahn's lawyers have said he attended "libertine" gatherings but didn't know some women present were paid.

The case is one part of an intercontinental legal saga that exposed Strauss-Kahn's active sex life and buried his French presidential ambitions.

Strauss-Kahn reached a settlement in New York last week with a hotel maid who accused of him of trying to rape her in May 2011.