Henri Sanson is a public executioner for the First French Republic, the son of Charles-Henri Sanson and part of the Sanson executioner dynasty. He executes Marie Antoinette, and in Mantel’s telling, he is executioner for Georges-Jacques Danton and Camille Desmoulins. It seems from Charles-Henri Sanson’s diaries that he, rather than his son Henri, carried out these executions.
For more information on Charles-Henri Sanson:
Charles Henri Sanson | British Museum
Charles Sanson: The Bloody Family History of the Guillotine | The Paris Review
Charles-Henri Sanson - Wikipedia