Convicted killer Charles Sobhraj, 78, returned to France on Saturday after nearly two decades behind bars in Nepal.
He was put on a flight at Kathmandu airport on Friday to take him to Paris via Doha.
Police believe Sobhraj was responsible for the deaths of more than 20 western backpackers on the so-called "hippie trail" through Asia in the 1970s and 1980s.
Nepal's Supreme Court ordered the release of the man known as the "bikini killer" in Thailand on Wednesday, on the basis of his advanced age and health.
A citizen of France, born to an Indian father and a Vietnamese mother who later married a Frenchman, Sobhraj landed at Paris's main international airport on Saturday morning and was escorted off the plane by police for identity checks.
"He is well, he is a free man," Sobhraj's lawyer Isabelle Coutant-Peyre said.
Asked what his next steps would be, she said: "He will file a legal complaint against Nepal because the whole case against him was fabricated."
Sobhraj had been held in a high-security prison in Nepal since 2003, when he was arrested on charges of murdering American backpacker Connie Jo Bronzich in 1975.
He was later found guilty of killing Bronzich's Canadian friend, Laurent Carriere, and had served 19 years out of a 20-year sentence.
But he was suspected of more murders, including in Thailand, where police say he killed six women in the 1970s, some of whom turned up dead on a beach near the resort of Pattaya.
He was jailed in India for poisoning a group of French tourists in the capital, New Delhi, in 1976, before he could stand trial on the charges against him in Thailand.
People who know him have previously described Sobhraj as a con artist, seducer, robber and murderer.
In 2021, the BBC and Netflix produced a drama series based on the story of Sobhraj’s alleged killings called The Serpent.
He is suspected of killing at least 20 people in Afghanistan, India, Thailand, Turkey, Nepal, Iran and Hong Kong between 1972 and 1982.
But despite multiple legal cases opened against him, judicial authorities across the region struggled to convict him for the killings — or to keep him behind bars.
He was arrested in New Delhi in 1976 and accused of murdering two tourists and stealing their jewellery.
He was convicted of the theft but acquitted of murder.
In Thailand, he faced 14 murder charges but avoided being extradited by staying before the courts in India until the Thai case expired in 1996. In Thailand, he would have faced the death penalty.
In 1986, he escaped from New Delhi’s maximum-security Tihar prison after luring guards into sharing a drug-laced birthday cake, but was later recaptured.
Sobhraj was deported from India in 1997 to France, where he lived freely but was investigated for allegedly trying to poison a group of French tourists in India.
He resurfaced in 2003 in a casino in the Nepalese city of Kathmandu, and was questioned about the unsolved murders of an American and a Canadian backpacker whose charred bodies were found on the city’s outskirts. He was convicted the following year and handed a life sentence.
Life sentences in Nepal are 20 years. In announcing his release this week, the Nepal Supreme Court said Sobhraj has heart disease, had already served more than 75 per cent of his sentence and behaved well in prison, making him eligible for release.
He was freed on Friday and ordered to leave Nepal within 15 days. A friend helped finance a ticket to France, and the French Embassy prepared travel documents allowing him to leave, lawyer Gopal Siwakoti Chitan said.
He was nicknamed “the serpent“ due to his reputation as a disguise and escape artist and was also known as “the bikini killer” because he often aimed for young women.
