One of the more challenging aspects of sustainability policies is to address social justice. Often, so-called sustainability initiatives turn out to be completely out of touch with the needs and expectations of the populations concerned, and contribute to increase social injustice. This is particularly true in urban areas, which are the ambit of this chapter. How to cope with this problem? Promoting people's place-based appropriation of sustainability policies looks like an interesting lead to follow. The challenge here is to address the social process of decision-making. Ultimately, the challenge is design a new social contract: matter in which a comprehensive understanding of the coordination mechanisms between the local, national, regional and international scale is crucial.