In April 1760, the property was acquired by Jean-Jacques Horneca who was a trader. Newly owner, he decided to transform the mansion by adding side wings, and therefore created independent attic ogee curved at the corners. The result given by the shape of the roof gives the building a picturesque silhouette, unusual in the Geneva area. Small roofs ” Imperial style” which give the building the look of a corner towers, is the most striking element. They are probably inspired by the Franche-Comté steeples. There is a similar treatment of the wings at the castle of “La Roche-sur-Loue” in “Arc-et-Senans” (Doubs, France). Once the volume increased, the house has been given a unified architectural decoration, such as to ensure it a new cohesion: chain boss and table, pediments, cords and window frames. Note that the approach chosen by Horneca to expand his home by adding two lateral wings was not an isolated practice in the Geneva context. The castle of Voltaire in “Ferney- Voltaire” and the Reposoir in Pregny, both transformed in the second half of the eighteenth century, are also good examples. In all three cases, the purpose was to adapt the building to aesthetic models in vogue and sophistication of modern comfort, tangible reflection of the owner’s aspirations.