The aim of this thesis is to examine the implementation of local policies in the field of the protection of urban heritage. This work seeks to overcome a legalistic approach of the tools of public action, to analyze their territorial dimensions, and to understand their effects on city centers. We have constructed a comparative approach considering the different forms of local "institutionalization". We have used this comparative approach to examine what "players"" did to enact heritage preservation regulations in three towns of the Loire Valley : Angers, Tours and Orleans. We have shown the role of the various tools in the process of heritage protection. This study analyzes these tools used to protect the heritage from the XIXth century to the present, and examines how the process confronts local realities. The forms of heritage policies implementation have been different in the three cities in their temporality, efficacy and territorial dimensions due to the choice of these tools. The objective of this study is to show how these tools are useful as keys to aid in understanding the stakes of patrimonialization of the old city centers. This study also examines the links between the expanding of heritage policies and the use of localized tools. In conclusion, it helps to grasp, in all its complexity, the local specificities of the implementation of heritage policies.
