The evolution of the artillery forces the engineers to work on the defenses of the citadel. It is suggested that the upper part of the citadel should be "defiled" by means of a vaulted platform which would leave the barracks and descend to the wrapping of the powder magazine.

This platform could be used as a place of arms and the two lateral walls, in solid ground, to the east and to the west, would be of sufficient height to serve as a mask wall and thus protect the soldiers from the views of the campaign.
The mask on the west side would be pierced with doors to access the shops under the platform and the east side would be crenellated to illuminate the shops.
This project was rejected, it was not until 1841 that it is required to raise a cross-piece from the barracks and that would join a wall of scrolling.
The latter would be attached to the envelope of the powder magazine.