In his first interview since his May 14 arrest over sexual assault accusations, Strauss-Kahn told France's TF1 television channel what happened between him and the maid, Nafissatou Diallo, "did not involve violence, constraint or aggression."
Still, he acknowledged, it "was not only an inappropriate relationship, but more than that, it was an error."
Strauss-Kahn, a Socialist politician who was widely considered a top contender in next year's presidential race until the case broke, said "it was a failing, a failing vis-a-vis my wife, my children and my friends but also a failing vis-a-vis the French people, who had vested their hopes for change in me.
"I think it was a moral failing and I am not proud of it. I regret it infinitely. I have regretted it everyday for the past four months and I think I'm not done regretting it," he said at the start of the 20-minute interview. Much of the exchange came off as staged, with Strauss-Kahn appearing calm and unruffled throughout and not surprised by the questions.
Strauss-Kahn's initial contrition was peppered with anger at his accuser, a Guinean immigrant who maintained he attacked her after she came into his room at New York's Sofitel hotel to clean.
He said the New York prosecutor concluded "Nafissatou Diallo lied about everything - not only about her past, that's of no importance, but also about what happened. The (prosecutor's) report says, it's written there, that 'she presented so many different versions of what happened that I can't believe a word."'
Strauss-Kahn suggested that financial motives might have been behind Diallo's accusations.
He also dismissed as "imaginary" separate claims by a French writer that he tried to rape her during a 2003 interview, again insisting "no act of aggression, no violence" had taken place between the two.
The writer, Tristane Banon, has maintained she and Strauss-Kahn tussled on the floor during an interview in an empty apartment, with the politician trying to open her jeans and bra and putting his fingers in her mouth and underwear.
"The version that was presented (by Banon) is an imaginary version, a slanderous version," Strauss-Kahn said.
Because a police investigation into the claims is ongoing, Strauss-Kahn said he would not say anything more about the matter. If Paris prosecutors decide to pursue the case, Strauss-Kahn could face a possible trial.
New York prosecutors dropped all criminal charges against him in the Diallo case last month, though Strauss-Kahn is still facing a lawsuit brought by the maid. He insisted he would not negotiate a settlement.
Asked whether he had any intention of returning to politics, Strauss-Kahn said he would "take time to reflect" and rest first.
"But all my life was consecrated to being useful to the public good," he said, adding "we will see."
Strauss-Kahn defended the large sums of money spent on his defense in the Diallo case. While he understood that they could seem shocking, "compared with the daily difficulties that French people face," he felt he had to do everything within his means to stay out of prison in Riker's Island in New York, where he was initially detained.
In addition to his legal team's fees, Strauss-Kahn was also initially subject to extensive and expensive bond conditions, including security measures estimated at about $200,000 a month, on top of the $50,000-a-month rent on a town house in New York's trendy TriBeCa neighborhood.
He lashed out at the U.S. justice system, which saw him paraded before a sea of cameras, looking rumpled, handcuffed and angry as plainclothes detectives took the then-IMF head from a police precinct to court. In France, images showing suspects in handcuffs are illegal.
"When you are snatched up in the jaws of that machine, you have the impression that it can crush you," he said. "I felt that I was trampled on, humiliated, even before I had the chance to say a word."
A small group of demonstrators gathered outside of TF1's Paris headquarters Sunday to denounce Strauss-Kahn. The protest was called by two feminist groups.
The AP does not name people who report being sexually assaulted unless they agree to be identified or come forward publicly, as Diallo and Banon have done.
Angela Charlton in Paris contributed to this report.