It plays on both its presence and its erasure, gently helping to create a fusion between the new and the existing. With regard to this structure, in some ways it's nothing more than a “cherry on the cake”, while demonstrating the renewed vitality of a museum that is pursuing the fine idea of an ever-evolving Roman town.
The addition of two small and uneven naves cements the contemporary image of the new building. Its volumes, which appear fragmented, reduce its impact on the view from the boulevard. The folds in their roofs bring the building within a familiar formal register which could ultimately be extended to cover all the remains.
In pursuit of an illusory timelessness in its relationship with what already exists, the cladding is made from cast-iron aluminum modules, uneven in size and texture, which contrast with the solid stone of the remains. Smiling on the boulevard Saint-Michel, this cast-iron texture changes color with the path of the sun, taking on the colors of the remains through reflections.
The three façades feature large swathes of metal guipure, their motif borrowed from the sculpted stone filigree, which is also present on the tambour of the staircase inside the chapel of the Gothic town house, one of the museum’s most emblematic spaces. This motif tattoos some of the cast panels and protects the small number of openings by diffusing a graphic yet gentle light. This identifiable symbol is also found on the external gate, an extension of the historic gate by the architect Albert Lenoir.
The building stands on the small number of micropiles available on the archaeological site, some of which remain visible and run through the ancient masonry, demarcating an archaeological reserve of around 250 m² that has been sadly neglected. Meanwhile, we needed to take all the necessary technical precautions in order to comply with the legitimate concerns of the archaeologists, in the exact place where “Lutèce was Lutèce” [or Lutetia].
From a technological point of view, the extension building stands on a series of micropiles that run through the Gallo-Roman structures. Laid on these two rows of piles spaced 12 meters apart, ground beams are embedded throughout the first 40 centimeters of the terrace, a thickness limited to prevent any disruption of the unexcavated surface.
Inside, the hall is structured by the framing of these remains, horizontally to the west towards boulevard Saint-Michel with a very open perspective and vertically to the north-east on the imposing façade of the frigidarium and overlooking the “salle des enduits”.
Materials both polished and untreated, wood and treated concrete, reveal a new ambiance inside the building. It was an opportunity to demonstrate the expertise of different firms in light of certain implementation requirements that we had to submit in order to limit a lazy choice of industrialized products that would be in total contrast with the quality of the previous constructions and the value of the collections. These materials evoke both the areas of archaeological excavations and the much more muted qualities of a medieval context.
The inner layout makes the most of the available heights by extending over three levels, one of which is only partial. As such, the museum improves its reception structures while also fulfilling its conservation role. With this extension, it extends its visitor route on the upper level with a small temporary exhibition room that visitors come to at the end of their tour, and with the enlargement of the final room on the permanent circuit in the Boeswillwald building.