20th-century French criminals

Christophe Caze (22 October 1969–29 March 1996) was a French terrorist and criminal, a former medical student in Lille, France. Caze was one of France's foremost terrorists.
Caze was raised Catholic. A medical student, he travelled to Bosnia in 1992 to practice medicine, working at the Zenica hospital. He converted into Islam and joined the Bosnian mujahideen in the Bosnian War, a unit that fought Jihad against Serbs. He became an extremist, and is reported to have played football with heads of decapitated Serbs. Abu Hamza al-Masri, who was a Bosnian mujahideen, was the religious guide of Christophe Caze. Another French convert was Lionel Dumont, who also joined the mujahideen.
He returned to France a radical Islamist, and became the leader of a GIA group based in Roubaix, the "Gang de Roubaix". The group robbed banks, armoured cars and supermarkets with machine guns and grenade launchers.In March 1996 the group planned to assassinate international leaders at the G7 meeting in Lille, using a car bomb. French police found the bomb, and then killed four in the group in an apartment shootout. Caze escaped but was shot dead the next day after trying to ram a police checkpoint, on motorway E17 near Kortrijk, Belgium. His address book was found to contain the contact information for Algerian resident in Canada, Fateh Kamel, another Bosnian mujahideen and suspect of militant ties.

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. He is suspected of the murder of about 60 to 200 victims during his lifetime, although the true number remains unknown.Despite showing early signs of mental illness and criminal behaviour, Petiot served in the First World War, graduated from an accelerated medical program, and began a dubious medical career that included performing abortions and supplying narcotics. His political career was marked by scandal, theft, and corruption. During the Second World War, Petiot operated a fraudulent escape network, offering safe passage to those wanted by the Germans for a fee, only to murder them, steal their valuables, and dispose of their bodies. In total, he was suspected of around 60 murders, but the remains of only 23 victims were found in the basement of his Paris home. Captured in 1944, Petiot claimed to be a Resistance hero who killed only the enemies of France. He was convicted of 26 counts of murder and was executed by guillotine in 1946. His life and heinous crimes have been depicted in film and comic books.

Henri Désiré Landru (12 April 1869 – 25 February 1922) (French pronunciation: [ɑ̃ʁi deziʁe lɑ̃dʁy]) was a French serial killer, nicknamed the Bluebeard of Gambais. He murdered at least seven women in the village of Gambais between December 1915 and January 1919. Landru also killed at least three other women and a young man in the house he rented from December 1914 to August 1915 in the town of Vernouillet, a town 35 km northwest of Paris. The true number of Landru's victims is suspected to be higher.Landru was arrested on 12 April 1919 at an apartment near Paris's Gare du Nord, which he shared with his 24-year-old mistress Fernande Segret. The police eventually concluded that Landru had met or been in romantic correspondence with 283 women during the First World War. Seventy-two were never traced. In December 1919, Landru's wife Marie-Catherine, 51, and his eldest son Maurice, 25, were arrested on suspicion of complicity in Landru's thefts from his victims. Both denied any knowledge of Landru's criminal activities. Marie-Catherine was released without charge in July 1920 due to health reasons. Maurice was released on the same day because the authorities could not establish his guilt.Landru continued to protest his innocence during the yearlong investigation. He was charged with the murders at Vernouillet and Gambais. This included the murders of ten women and his first victim's teenage son. Landru's trial in November 1921 at Versailles was attended by leading French celebrities, including the novelist Colette, and the actor and singer Maurice Chevalier. On 30 November, Landru was found guilty by a majority verdict of all eleven murders and sentenced to death. He was executed by guillotine on 25 February 1922.