Our paper aims to analyze the economic and urban changes undertook by French and Swiss cities and stressed in the two concepts of sustainability and changeability (“mutabilité” in French). Its goal is to assess how these two concepts can be opposite, convergent or synonymous when they relate to urban regeneration. Such a comparative work renews the analysis of today’s planning policies. As sustainability can be considered as one of the key paradigm of planning guidance and policies since the last fifteen years, changeability can be used to describe the regeneration of derelict spaces, in other words, brownfield lands. Therefore, the convergence between changeability and sustainable development may appear as obvious as both relate to the perspective of implementing a more compact city. However, we will notice thanks to three different cases studies, that changeability cannot be always considered as a synonym to sustainability.