A spokesperson at the prosecutor's office in the northern France city of Lille said investigators had presented evidence Strauss-Kahn, the former chief of the International Monetary Fund, may have sexually assaulted a Belgian prostitute at a sex party at the W Hotel in Washington in December 2010, The New York Times reported.
Last month, Strauss-Kahn was charged with "aggravated procurement in an organized gang," a legal term for pimping, over alleged involvement in a prostitution ring based in Lille, the Times said.
French newspaper Liberation said a Belgian prostitute at the party told police she had been subjected "certain sexual acts without her consent."
Prosecutors were to evaluate evidence before deciding whether to file charges, the Times said.
A judge ruled this week a New York hotel maid's civil suit claiming Strauss-Kahn had sexually assaulted her in May 2011 can go forward, the New York Daily News reported.
The judge ruled the former IMF leader isn't entitled to diplomatic immunity.
The News said Manhattan District Attorney Cyrus Vance has decided against prosecuting Strauss-Kahn because of doubts about whether the maid could be trusted.