The Paris prosecutor's office said Friday it has opened a preliminary investigation into accusations by a French writer that former International Monetary Fund chief Dominique Strauss-Kahn attempted to rape her in 2003.

Tristane Banon filed a complaint earlier this week, saying Strauss-Kahn attacked her in an empty apartment during an interview for a book.

Lawyers for Strauss-Kahn have said they would file a slander suit against Banon. Strauss-Kahn has called her account “imaginary.”

The attempted rape allegation in France against Strauss-Kahn comes as sexual assault charges against him in the United States are teetering on the brink of collapse. He was released from house arrest in New York last week after prosecutors said there were questions about the credibility of the hotel maid who in May accused him of sexual assault.

The charges are still pending against him, with another court date set for July 18. He is free to travel within the United States, but prosecutors have retained his passport, keeping him from returning home to France.

He has denied the maid's allegations. Strauss-Kahn, once deemed the Socialist frontrunner to take on French President Nicolas Sarkozy in next year's election, resigned as the IMF chief to fight the New York allegations.

Banon first spoke about her encounter with Strauss-Kahn in 2007, but did not press charges after her mother said it would damage her career. Her mother has since said she regrets giving her daughter that advice.

The writer changed her mind about pursuing a complaint against Strauss-Kahn after the New York case became public.