Since it emerged in May that Dominique Strauss-Kahn had been arrested for the "criminal sexual act, unlawful imprisonment, and attempted rape" of a hotel maid, France's Socialist Party has been mourning the loss of a rival to President Nicholas Sarkozy.
But after mounting questions over the maid's credibility, on Monday New York prosecutors asked a judge to drop the case because they said they were "no longer convinced of the defendant's guilt beyond a reasonable doubt".
They said the maid had not been truthful "on matters great and small".
The 62-year-old will learn today whether the charges are to be dropped.
Martine Aubry, the leader of the Socialist Party, said it was an immense relief. She told a French radio station: "We were all waiting for this...for him to finally be able to get out of this nightmare."
If the charges are dropped Mr Strauss-Kahn will still face a civil case brought by the maid, but will be free to return to France to attempt to rehabilitate his political career before April's elections.