What was thought lost has reappeared at 8 rue des Tournelles. The Versailles residence of Jacques Hardouin‑Mansart de Sagonne, architect of Saint‑Louis Cathedral and grandson of Jules Hardouin‑Mansart, has revealed an unsuspected past. He lived there from 1742 to 1754, and it was in the courtyard of this house, nicknamed the “Maison du Modèle,” that Louis XV inspected on 8 May 1742 the stone model of the future cathedral after the laying of its first stone.

The Antoine de Gironde Architecture Atelier is acting as project manager for this restoration, which has received the Fondation du Patrimoine label. Nearly three centuries later, careful removal of the renders uncovered an 18th‑century ashlar façade, finely dressed and concealed since the Restoration.

This delicate work brought several remarkable features to light :

An exceptional ashlar arrangement, with ochre and brick‑red colored pointing and traditional wooden wedges.

A clearly legible upper cornice, revealing the original height of the façade.

An understanding of the complete 19th‑century transformation: raising of the building, tooling of the stone faces, and application of a neo‑classical decorative render.

These discoveries raised essential questions: should the ashlar façade be reinstated, or should the neo‑classical decoration be preserved?

In consultation with the Maison de l’Architecture et du Patrimoine, we chose an approach respectful of the building’s different historical layers. The decision was to restore the neo‑classical décor while leaving exposed the non‑tooled stone faces at the revealed plane of the façade. To recover the original stone hue in the renders, a fragment was sampled and analysed in collaboration with a local plaster manufacturer. Finally, the famed “château yellow” of the carriage‑door — witness to Louis XV’s visit — was found beneath several paint layers and has been reinstated.

To discover is to make choices about what we pass on. Revealing a buried past is about finding a balance between memory, coherence and emotion.