With a width of 1.40 m and a height of 5 m, the house no. 39 in rue du Château-d'Eau is considered the smallest of Paris. Originally there was a passage to Faubourg Saint Martin. It is alleged that an inheritance dispute has led to the construction of the hose on this passage. In the ground floor, a shop is located (then as now). On the first floor, which can only be reached via the neighboring house, there is a room which used to be a living space and is now used as a warehouse for the shop.