Both parties have been interviewed by police over the alleged incident.

“The police unit asked me whether I was prepared to accept a confrontation. Obviously, I said: ‘Yes’. I want him in front of me so he can look into my eyes and say to my face that I imagined it,” Banon said last week.

Strauss-Kahn has lodged a lawsuit for slander against Banon over her claim, which he has called “imaginary”.

The 62-year-old’s career as managing director of the International Monetary Fund came crashing to an end in May when a New York hotel chambermaid accused him of sexual assault and he was arrested.

The case dashed his hopes of winning the French Socialist Party’s nomination to run for president next year, but his multimillionaire heiress wife stood by him and paid for a luxury Manhattan townhouse during his house arrest.

The New York prosecutor’s case collapsed last month after doubts emerged over the credibility of his accuser, Guinean immigrant Nafissatou Diallo, and the man the French call “DSK” made a triumphant return to Paris.

But French police were waiting to interview him about Banon’s allegations, which she first made publicly on television in 2007 and brought to magistrates this year after the New York case came to light.

She has claimed that Strauss-Kahn — 30 years her senior and a friend and one-time lover of her mother — lured her to an unfurnished Paris flat in 2003 on the pretext of offering her an interview for a book she was writing.

She descibes him grabbing her “like a rutting chimpanzee”, attempting to pull off her jeans and forcing her to kick and shout before escaping.

According to a source close to the inquiry, Strauss-Kahn told investigators that he had “made an advance” on her but had backed down on receiving a refusal and had at no point been violent or attempted to force himself on her.

Banon’s complaint is for attempted rape rather than sexual assault, and if the prosecutor decides to downgrade the charge Strauss-Kahn would not be charged on the lesser crimes because of the statute of limitations.

Regardless of the result of the criminal inquiry, Banon has vowed to lodge a civil suit against him, even as Strauss-Kahn will pursue his defamation suit against her. Diallo is also seeking damages in a New York civil case.

Strauss-Kahn was the pollsters’ favourite to win next year’s presidential election and oust the unpopular incumbent Nicolas Sarkozy, and the cases have provoked a political earthquake in France.

The ongoing Socialist primary campaign is now a more open race, with former Strauss-Kahn rival Francois Hollande expected to win.

In a television interview, Strauss-Kahn said he had abandoned his presidential bid for now.