Abstract : Urban sustainability dynamics can be identified through territorial tools: Agendas 21, Climate Plans and sustainable neighborhood projects, conducted most of all by local authorities. Even if the Parisian metropolis is behind as regards sustainability, a patchwork of initiatives grows, led by engaged stakeholders: it shows the generalization in progress of urban sustainability, which brings other stakeholders to action. Nevertheless these initiatives face forces of inertia, linked to a concentration of territorial stakes which are difficult to seize for stakeholders. Whereas taking the metropolis as scale of action is the most relevant option in regards to urban sustainability, sustainability politics are not accomplished on that scale, which is not truly a proper territory. On the contrary, sustainability projects are designed as dependant of metropolitan projects. Agendas 21 and Climate plans do not territorialize their action. Sustainable neighborhood are planned to favour urban continuities and fit in their urban "milieu". But these levers of action stay limited because they are not enough connected. Citizens are improperly mobilized however they can become a sustainability force. This thesis contributes to an environmental geography of sustainability, based in "milieux" and territories, bringing forth concepts and methodologies (assessment by indicators, and survey techniques).