Charles-Henri Sanson is pretty famous.. how about his siblings? The internet doesn't provide much, what can you say about them? 🙏
If you speak or read French, it is possible to get some info on them by reading Jacques Delarue, or the National Archives.
Now, what I found about the forth generation sibblings can be compiled in the two dictionaries written by Michel Demorest, namely "Dictionnaire historique et anecdotique des bourreaux" and his later one "Dictionaire généalogique des familles de bourreau" (of which I only had time to make very rough notes) as well as the description of the Sanson house, which was done to split the fortune amongst the many heirs of Charles-Jean-Baptiste Sanson.
So,
Madeleine-Claude-Gabrielle Sanson, was born in around the winter 1738 (reconstituted given the birth date of her younger brother and her father's age at time of mariage). She was married off in January 1754 to Pierre Hérisson, ten years her senior, executioner of Melun, around age 16. Of the mariage, five daughters would be born. She died before August 1779. Her eldest daughter, Marie-Madeleine-Geneviève, married Louis-Cyr-Charlemagne Sanson, her own uncle. She's Charles-Henry's only full-blood sibbling.
Louis Charles Martin Sanson, born in 1744, executioner of Tour. He married Marie Victoire Collet de Charmoy in 1787, who turned out to be a quite bloodthirsty and violent woman. From the marriage would resulta son, Louis-Victor. During the Revolution, he became the protégé of Sénard, and was influential in fanatic circles. He also was poltically active, and attempted to become member of the Surveillance Comity, of which he was thankfully banned from doing so, although he was in position for a short while during the Terror, and arranged the results to his financial benefits. He was also apperently neglectful and corrupt at his actual job. He would publically strip the condemned, to their shifts, and would publically strip their corpses. He eventually calmed down after being tried for his corruption. He became executioner of Dijon after wards, job he hated because of the life-threatening ostracism he was subject to, so he played sick.
Nicolas-Charles-Gabriel Sanson II: Born 1745. He was executioner of Versailles from 1765 to 1778, then 1779 he became torturer until the abolition of his office. He then became executioner of Blois, were in 1795 he married the widow Anne François, of unknown surname. Appearently, his stint as a torturer caused him to become a hardcore alcoholic. He switched to Montpellier, 1800, age 55, where he died from an alcohol poisonning too many.
Élisabeth Sanson: Born around 1747, married Pierre François Verdier at age 18.
Louis-Cyr-Charlemagne Sanson: Born 1748, and died in 1794, age 46 years old. In 1760, he became assistant to his older brother Charles-Henry, age 12. He became executioner of Provins 1768, age twenty. He left the post in 1788 to become executioner of Versailles. In 1779, year of his father's death, and actually a bit after, he married his own niece Marie-Madeleine-Geneviève Hérisson. The couple would have children, none of whom would survive past infancy. During the French Revolution, he became an activist for his profession and supported his son's career after he quit the executioner thing to work as a locksmith. The 10th of August 1792, he was arrested on charges of royalism, and released two days before the massacres of September. That same year, he married Marie Fare Gendron, after she had fallen pregnant with his child, a boy who would survive to adulthood. His death appearently caused a bureaucratic hellscape for the judicial authorities. His widow would come to live with Charles-Henry.
Marie-Josèphe Sanson : Born 1752, died in 1819 or 1813, depending on sources. She married her first cousin Jean Louis Sanson around 1773, at the age of around 22, while he was around was around 24. They had two children, with a daughter that would survive into adulthood. After her husband's disgrace from office and premature death, she would succeed in escaping infamy to become a "ouvrière en linge" after the Revolution. She was one of the rare members of an executioner family to successfully integrate society.
Pierre Charles Sanson: Born in 1753. He became assistant to his older brother, officially so in 1792, but he became sub-lieutenant of the Cannonier in 1794, and Master Carpenter. He treated patients, and that's what we know of him.
There were other sibblings, this ask took me long enough. I'll get you another one if you want to.