IMF chief Dominique Strauss-Kahn has consented to a medical examination over allegations of serious sexual assault.
Mr Strauss-Kahn, who was arrested in New York, denies charges of attacking and attempting to rape a hotel maid.
His court hearing scheduled for Sunday was postponed until Monday to allow forensic tests to be carried out.
French writer Tristane Banon is considering legal action against Mr Strauss-Kahn for an alleged sexual assault in 2002, her lawyer said.
Ms Banon, 31, claimed Mr Strauss-Kahn attacked her when she went to interview him. She chose not to file suit against him at the time.
Mr Strauss-Kahn, a former finance minister, has until now been considered a frontrunner to be the Socialist candidate for president in 2012.
He had been scheduled to meet German Chancellor Angela Merkel on Sunday in Berlin and then attend an EU finance ministers' meeting in Brussels on Monday on bailouts for Portugal and Greece.
Correspondents say he has been central to efforts to stabilise the finances of struggling eurozone member states and his detention is likely to complicate the process.
The Euro fell half a cent to $1.4063 when Asian markets opened on Monday - a six-week low against the dollar - reflecting concerns about the impact the arrest could have on bailouts plans for Portugal and Greece.
Mr Strauss-Kahn - often referred to in France simply as DSK - was detained at JFK airport on Saturday night as he prepared to fly to Europe.
He is believed to have been in New York on personal business. He does not have diplomatic immunity, a New York police spokesman said.
The 62-year-old was kept overnight in a special unit for sexual harassment in New York's Harlem district. On Sunday he was charged with a "criminal sexual act, unlawful imprisonment, and attempted rape".
Police say the 32-year-old woman who made the allegations has formally identified him in a line-up.
Mr Strauss-Kahn's clothing will be tested for DNA traces, the New York Times reported.
Speaking outside court in Manhattan, lawyer William Taylor said Mr Strauss-Kahn had "willingly consented to a scientific and forensic examination", adding that he was "tired but fine".
A second lawyer, Benjamin Brafman, said his client "intends to vigorously defend these charges and he denies any wrongdoing".
Mr Strauss-Kahn's wife, prominent French journalist Anne Sinclair, has also said she believes he is innocent.
"I do not believe for one second the accusations brought against my husband," she said in a statement sent to the AFP news agency on Sunday.
The BBC's David Chazan, in Paris, says there has been a mixed reaction to the arrest in France, with some people seeing it as a national humiliation but others suggesting that he might have been set up by his political opponents.
Mr Strauss-Kahn was widely expected to announce his intention to run for the French presidency soon, and was seen as having a genuine chance of beating President Nicolas Sarkozy.
Paris regional councillor Michelle Sabban told AFP: "I am convinced it is an international conspiracy... This is a new form of political assassination."
Socialist legislator Jean-Marie Le Guen said: "The facts as they were reported today have nothing to do with the Dominique Strauss-Kahn whom we know."
Meanwhile, a centre-right opponent of Mr Strauss-Kahn's, Dominique Paille, said if the allegations were true, it would be "an historic moment, but in the negative sense, for French political life".
"I hope that everyone respects the presumption of innocence. I cannot manage to believe this affair," he told French TV.
But the leader of the National Front party, Marine Le Pen, said Mr Strauss-Kahn had been "definitively discredited".
Mr Strauss-Kahn has won praise for his stewardship of the IMF, which he has guided through difficult times including the recent world financial crisis.
In 2008, he was criticised by the IMF board for an affair with a subordinate member of staff. The board said the affair had been consensual but reflected a "serious error of judgement".
John Lipsky has been appointed acting managing director of the IMF in his absence.
The fund's director of external relations, Caroline Atkinson, said the organisation remained "fully functioning and operational".