A French novelist will file a criminal complaint on Tuesday accusing Dominique Strauss-Kahn of attempted rape, her lawyer said, throwing fresh uncertainty into a fierce national debate about whether the former International Monetary Fund chief can return to his country's presidential race.

A sexual assault case against Strauss-Kahn in New York has been badly weakened by questions about his accuser's credibility. As a result, France was consumed Monday  by the question of whether the longtime Socialist Party politician would revive his dream of running against unpopular conservative President Nicolas Sarkozy.

The political world was hit by a new shock when the lawyer for writer Tristane Banon announced she planned to file the complaint in Paris within a day.

Banon came forward after Strauss-Kahn's May 14 arrest in New York to accuse him of wrenching open her bra and trying to unbutton her jeans in 2002. Lawyer David Koubbi said Banon had been dissuaded at the time from filing charges by her mother, a regional councillor in Strauss-Kahn's Socialist party.

Koubbi also had said his client had no intention of pressing charges while the American prosecution was going on because the two cases should be kept separate. Now, Banon is pressing forward, Koubbi told The Associated Press.

However, lawyers for Strauss-Kahn said Monday they will file a slander complaint against Banon, calling her allegations "imaginary."

Messages of support for the complaint quickly appeared on Banon's Facebook page.

Before Koubbi's announcement, the country was split on whether it wanted Strauss-Kahn back in public life: two polls showed an almost even division between those who thought he should return, and those who believed his political career was over.

The former IMF chief's re-entry to politics would be a tectonic shift in a campaign already shaken by his arrest on charges of attacking a New York hotel maid. The Socialist had been widely seen as the leading contender in the 2012 election, leading polls in the months before his arrest.

With the alleged victim's credibility undercut and Strauss-Kahn free on bail, French politicians and pundits appear to almost uniformly assume that the charges against him will be dropped in coming weeks.

For many, the question is now whether a man paraded in handcuffs before photographers outside a Harlem police station a month and a half ago will try to run against widely unpopular conservative president Nicolas Sarkozy and become leader of the world's fifth-largest economy.

"DSK Back?" the left-leaning daily Liberation asked on its front page Monday, describing Strauss-Kahn's release from house arrest as having turned the Socialist primary race upside down for the second time in as many months.

"Dominique Strauss-Kahn will express his intentions when he wants to," Socialist Party leader Martine Aubry told France-2 television.

The charges still stand against Strauss-Kahn, who has relinquished his passport to authorities in New York. Another court hearing would be needed for him to get it back. His next appearance is scheduled for July 18, five days after the deadline for candidates to register in the Socialist Party primary.