In view of the work of implantation of the future museum of the Great Century, archaeologists carry out preventive excavations in the courtyard of the former Sully barracks. Intended to last 9 months they will allow to know more about the history of the human occupation of the site. The diagnosis revealed remains that extend from the end of prehistory to the contemporary period. The first surveys found elaborate and sometimes burnt flints, ceramic furniture, the attribution of which tends towards the thirteenth-fourteenth centuries and which were partially destroyed by the construction of the castle of Saint-Cloud in the seventeenth century. From this time the excavations allow to detect the traces of earthworks and masonry related to the expansion of the gardens towards the Seine, in the form of vegetable garden or garden of pleasure, even of the greenhouse frequented by Marie-Antoinette...