Our research allowed us to understand that the process of devaluing the site of Bab El Quarmadine is divided into three main axes influencing each other. The first is legislative with passive, truncated, and poorly enforced regulation, resulting in inappropriate interventions and practices. The second is its disintegration of the urban fabric which is the fruit of French action, which first dismissed the site relegating it to extramuros then isolated it with the passage of the railroad, which currently represents a real break to the urban development. The third is social with this gradual dissolution of the affective bond since colonization because of the lack of practice and use of space. Despite the various interventions on the site, and especially that of 2010, it is still isolated, somewhat hostile, and misunderstood by society. These interventions have always been conditioned by time and the budget envelope, and apart from its maintenance, they have not succeeded in enhancing it. It also shows that this is not an isolated case in Tlemcen or elsewhere in Algeria, because it has many similarities with other elements of the defensive patrimony which show the same symptoms of devaluation and are provoking today more than ever, the greatest attention