There was a gang in Paris from 1830 to 1835, described as a "quartet of bandits," which was actually made up more than four men.  The four whose names are mentioned in the book, Claquesous, Gueulemer, Babet, and Montparnasse, are merely the leaders of a network of criminals, referred to as a "monstrous polyp of evil."  Society referred to this gang as "Patron Manette," which means morning, perhaps because all of their work was done at night and they were finished by morning.  In a way, this gang was to blame for any criminal activity the police could not catch.  This is the group who Thenardier is working with while he is under the alias Jondrette.