Marcel André Henri Félix Petiot (17 January 1897 – 25 May 1946) was a French medical doctor and serial killer.

He was convicted of multiple murders after the discovery of the remains of 23 people in the basement of his home in Paris during World War II.

During the Second World War, Petiot operated a fraudulent escape network, offering safe passage to those wanted by the Nazis for a fee, only to murder them, steal their valuables, and dispose of their bodies.

Petiot was ordered to undergo a psychiatric evaluation, resulting in charges being dismissed when it was judged that he had a mental illness.

[citation needed] Later accounts make various claims of Petiot's delinquency and criminal acts during his youth, but it is unknown whether they were invented afterwards for public consumption.

While working at Villeneuve-sur-Yonne, he gained a reputation for dubious medical practices, such as supplying narcotics and performing illegal abortions, as well as for petty theft.

In Paris, Petiot attracted patients by using fake credentials, and built an impressive reputation for his practice at 66 Rue de Caumartin.

He supposedly developed secret weapons that killed Germans without leaving forensic evidence, planted booby traps all over Paris, had high-level meetings with Allied commanders, and worked with a (nonexistent) group of Spanish anti-fascists.

Using the codename "Dr. Eugène", Petiot pretended to have a means of getting people wanted by the Germans or the Vichy government to safety outside France.

Petiot claimed that he could arrange a passage to Argentina or elsewhere in South America through Portugal, for a price of 25,000 francs per person.

Three accomplices, Raoul Fourrier, Edmond Pintard, and René-Gustave Nézondet, directed victims to "Dr. Eugène", including Jews, Resistance fighters, and ordinary criminals.

Once victims were in his control, Petiot told them that Argentine officials required all entrants to the country to be inoculated against disease, and with this excuse injected them with cyanide.

He purchased the house the same week that Henri Lafont returned to Paris with money and permission from the Abwehr to recruit new members for the French Gestapo.

On 11 March 1944, Petiot's neighbours in Rue Le Sueur complained to police about a foul stench in the area and large volumes of smoke billowing from a chimney of the house.

[8] During the intervening seven months, Petiot hid with friends, claiming that the Gestapo wanted him because he had killed Germans and informers.

During the liberation of Paris in 1944, Petiot adopted the name "Henri Valeri" and joined the French Forces of the Interior (FFI) in the uprising.

He said that he had discovered the pile of bodies in 21 Rue le Sueur in February 1944, but had assumed that they were collaborators killed by members of his Resistance "network".

Celebrity attorney René Floriot acted for the defence, against a team comprising state prosecutors and twelve civil lawyers hired by relatives of Petiot's victims.

Petiot taunted the prosecuting lawyers and claimed that various victims had been collaborators or double agents, or that vanished people were alive and well in South America using new names.

On 25 May 1946, Petiot was beheaded, after a stay of a few days due to a problem with the release mechanism of the guillotine, and buried at Ivry Cemetery.

The Butcher of Paris, written by Stephanie Phillips with art by Dean Kotz, is a 2019 five-issue comic book mini-series that dramatized the investigation, arrest, and eventual conviction of Petiot.