The small tower erected at number 70 rue du Gros Horloge in Rouen is set against one of the most famous buildings of the town, in the heart of the commercial district. Restoration works started urgently after the fall of stonework onto the public road. The studies which were first carried out revealed both the dramatic sanitary situation of the building and the different successive works which over the ages had considerably transformed its general aspect. It is the latest known aspect of the building which was privileged by the restoration project, in harmony with the Gros Horloge and well documented by an important number of photographs dating back to the beginning of the 20th century. Decorative plaster elements from the façades and lead ornaments from the roof were thus reconstructed. This project, which was carried over a short span of time, did not imply the closure of the boutique on the ground floor, despite important restoration work on the exterior wooden paneling.