The elevator seen from a semi-vault, where one can see site stone in different states: raw still on the mountain, carved in the 19th century to create buildings, in little stones to fill the gabions.

© Atelierpng

Landscape photography taken near the Rhone river flowing at the bottom of the two forts, with the contemporary railway linking France and Switzerland.

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The refurbishment of the welcoming volumes has been thought so that it could endure severe climatic conditions: galvanized steel and bricks.

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Narrow openings have been made in reference to arrow slits that can be found on regular defensive castles. They offer snapshots of the surroundings.

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The entire stones that have been put into the gabions come from the little demolitions needed to give access tot he different levels oft he castle, making this project an example of reuse.

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Site plan showing the Alps, Jura Mountains and the Rhone flowing between them, generating the Défilé de la Cluse where the fort is standing.

© Atelierpng

Main plans from ground to terrace.

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Main elevation of he elevator from the main court, showing it fits the existing buildings and goes above them to give access to the roof terrace.

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Axonometric drawing of the metallic and brick slab allowing the installation of the museum within the Porte de France.

© Atelierpng

Axonometric drawing showing the principles of reuse and the harmlessness of the architectural setting.

© Atelierpng

Built in the seventeenth century the fort and its site are much alive. Their uses oscillated according to the periods of war and peace, between landscape asset and military gem and resulted in the successive historical layers of this imposing construction made with the Jura Mountains. Atelierpng questions the nature of works and their dating, seizes it in order to integrate as well as possible in the successive historical layers of this imposing construction, which is the rock of the Jura. Historically housed on a hillside, to better see the adversary's arrival, the fort today shows an exceptional landscape: the banks of the Rhone, the massifs of the Ain and those of Haute-Savoie. The revaluation ("revalorization") of the fort tells the military history of the place, its architecture and its materials, its singular position anchored in the massif.

Historically housed on a hillside, to better see the opponent coming, the fort today shows an exceptional landscape. The revaluation of the fort tells the military history of the place, of its architecture and materials, of its singular position anchored in the massif. The first intervention is the requalification of the reception areas, on the ground floor of one of the casemates. Without disrupting the rigour of the skilfully cut stone that makes up the identity of the fort, the architects chose to install metal elements that are integrated into the vaults and resist the particularly difficult climatic conditions. The new vertical circulation of the fort can be seen from the entrance to the Porte de France for the trained eye, while it is clearly visible from the inner courtyard. The operation boasts an unvarnished geometry, in resonance with the rigour of the fort l'Écluse, cut to withstand the harshest of winters. The loopholes negotiated between the gabions frame views towards the landscape and military environment.

The most visible intervention, the vertical circulation is carried out in gabion chosen for its unfailing material link with Fort l'Écluse, patiently built on the rock of the Jura. The galvanised steel cages were filled exclusively with the products of the demolitions linked to the intervention, in a virtuous logic of recycling. The delicate conditions of the site, in the heart of a high perched fort, led to the use of prefabrication and the notion of a dry site. The cuts and removals necessary for the installation of the structure were carried out in a logic of parsimony and economy of means. The stones resulting from the cuttings were sorted and crushed in order to obtain the raw material for the project. Two thin walls of gabions were erected and filled in place with these demolition products. Snapshots of the construction site. The same principle of prefabrication and "dry" assembly was proposed for the floors: galvanised metal frames were filled with flooring.