Former IMF chief Dominique Strauss-Kahn cleared security at a New York airport Saturday before boarding a flight headed to France, after sensational sexual assault charges against him were dropped.

Strauss-Kahn and his wife Anne Sinclair made their way through a crowd of journalists at John F. Kennedy International Airport before they were helped through a security checkpoint, an AFP correspondent saw.

Strauss-Kahn, 62, resigned as the International Monetary Fund's managing director in May after he was arrested at Kennedy airport and charged with the sexual assault and attempted rape of a hotel maid in New York.

Last week, he walked free when a judge dismissed charges against him. Prosecutors said they could not pursue the case because the accuser's lies had made it impossible to prove her accusations beyond a reasonable doubt.

Strauss-Kahn, who was wearing a dark suit and white shirt but no tie, smiled and waved to a group of passengers but did not speak to reporters. He did not check in at the Air France counter before going through security.

Air France operates several flights from New York to Paris, but the time given by members of his inner circle would indicate he was traveling on AF 007, which was scheduled to depart at 7:15 pm Saturday.

The respected French economist and former finance minister had been expected to be President Nicolas Sarkozy's main challenger in 2012 elections before the scandal broke in May, but the saga has left his political career in tatters.

His imminent return has caused embarrassment for France's opposition Socialist Party as it prepares to vote in a primary to choose a candidate to run against Sarkozy.

"I'm eager to return to my country," Strauss-Kahn told reporters outside his home in Lower Manhattan on August 23 after the charges against him were dropped, calling the legal saga a "terrible and unjust ordeal."

"I'll express myself at greater length once I'm back in France."

In a written statement, he said the three-month-long legal process had been a "nightmare for me and my family."

The case against Strauss-Kahn began to unravel weeks after his arrest when prosecutors said his accuser had been caught lying on her asylum application form, including about a gang rape she had suffered in her native Guinea.

Strauss-Kahn's legal travails however are not yet over.

The New York hotel maid, Nafissatou Diallo, has filed a civil suit seeking unspecified damages against Strauss-Kahn.

In a separate case in France, 32-year-old writer Tristane Banon has filed a complaint alleging the Socialist politician tried to rape her after luring her to a Paris flat in 2003.

Strauss-Kahn has announced his intention to sue Banon for defamation, alleging she invented the story to help publicize her writing.