Jean Valjean began by committing a blunder. He thought that he was beneath the Rue Saint-Denis, and it was a pity that it was not so. Under the Rue Saint-Denis there is an old stone sewer which dates from Louis XIII

and which runs straight to the collecting sewer, called the Grand Sewer, with but a single elbow, on the right, on the elevation of the ancient Cour des Miracles, and a single branch, the Saint-Martin sewer, whose four arms describe a cross. But the gut of the Petite-Truanderie the entrance to which was in the vicinity of the Corinthe wine-shop has never communicated with the sewer of the Rue Saint-Denis; it ended at the Montmartre sewer, and it was in this that Jean Valjean was entangled. There opportunities of losing oneself abound. The Montmartre sewer is one of the most labyrinthine of the ancient network.