In Paris, former convict turned police informant Eugène François Vidocq was appointed to lead the newly formed Brigade de la Sûreté, France's plainclothes criminal investigation unit. Vidocq pioneered undercover work, the use of criminal informants, the systematic filing of criminal records, and the matching of evidence to suspects through his intimate knowledge of the criminal underworld. His career revolutionised detective practice in France and became the model for professional criminal investigation across Europe.

Vidocq's life and methods directly inspired two of literature's most iconic figures: Balzac's master criminal Vautrin and Victor Hugo's Javert in Les Misérables draw heavily on Vidocq's dual identity as criminal and lawman. He also influenced Poe's creation of Auguste Dupin, the prototype for all literary detectives, making Vidocq a foundational figure in the birth of detective fiction as a genre.