Born in 1775, Vidocq was but a lad during the French Revolution. He spent his youth as a petty thief and was frequently in jail. However, his association with thieves was to prove beneficial. By the Napoleonic era, he was working as an informant for the police and eventually, became a policeman himself. *
* They usually say crime doesn't pay. For this fellow it not only paid, but came with a pension and medical.
In fact, he was one of the forefathers of the deductive method of crime-solving and founded a unit that grew to become the Sûreté, France's premier crime-fighting organization. He always worked both sides of the law, but his criminal friends proved invaluable to him as a detective.