The prosecutor's office in Lille, France, said Tuesday the investigation into Dominique Strauss-Kahn's involvement was ended after the Belgian woman who testified she was gang-raped said she would not file charges, CNN reported.
Strauss-Kahn, 63, is still under investigation for his possible involvement in a prostitution ring.
Police investigating the alleged prostitution ring heard testimony from the Belgian woman that she was gang-raped and referred the case to the French prosecutor.
The prosecutor's office said Tuesday the woman's lawyer stated in August she didn't want to give a statement and that the woman had written a letter to the prosecutor saying the sex had been consensual.
At the time the woman was questioned late last year she had not filed a complaint.
Strauss-Kahn has denied all the allegations and has not been charged.