The design of The Citadel originated from the idea that the centre of a new city needs historical references without engaging in mere architectural historicism. Architect ChristianDe Portzamparc found inspiration in medieval citadels and created a modern version, consisting of four quadrants. Shops are located at ground level, topped by a projecting concrete ridge that refers to the geological layers of the earth below. Beyond that ridge lies a quiet residential area built around a large green field – in effect, the homes’ gardens.