Diallo (33) and Strauss-Kahn (63) crossed paths when she arrived to clean his luxury Manhattan hotel suite.
She told police he chased her down, tried to yank down her underwear and forced her to perform oral sex.
The allegation let loose a spiral of accusations about the sexual conduct of Strauss-Kahn, a married diplomat and economist who had long been dubbed the "great seducer."
He now faces charges linking him to a suspected prostitution ring in France.
Prosecutors in New York dropped charges against Strauss-Kahn in August 2011, saying Diallo had lied about her past -- including a false account of a previous rape -- and her actions after leaving Strauss-Kahn's room.
Diallo, who's from Guinea, said she told the truth about their encounter.
Diallo had sued Strauss-Kahn in the meantime, with her lawyers saying she would get her day in a different court. Strauss-Kahn called the lawsuit defamatory and countersued her for $1m (¤0.7m).
She also sued the New York Post over a series of articles that called her a prostitute and said she sold sex at a hotel.
That case has also been settled. A News Corp spokeswoman declined to comment.
Since the allegation was first made, Strauss-Kahn has found himself plagued by accusations of sexual misconduct that further tarnished his reputation.
The Socialist had been seen as a potential leading candidate for the French presidency before his New York arrest.
In France, judges are to decide by December 19 whether to annul charges linking him to a suspected prostitution ring run out of a luxury hotel in Lille.
He acknowledges attending "libertine" gatherings but denies knowing that some women present were paid.
In August, a separate case against Strauss-Kahn, centred on allegations of rape in a Washington DC hotel, was dropped after prosecutors said the accuser, an escort, changed her account to say she wasn't raped.
Soon after Strauss-Kahn's arrest in New York last year, French writer Tristane Banon accused him of attempting to rape her during an interview in 2003, a claim he called imaginary and slanderous.
Prosecutors said they believed the encounter qualified as a sexual assault, but the legal timeframe to pursue her complaint had elapsed.
Strauss-Kahn has separated from his wife, journalist and heiress Anne Sinclair, who stood by him through the allegations in New York.