International audience This article investigates the conditions necessary for the emergence of the city as a space for political action. It draws on the example of transport policies in Greater Geneva, where the pursuit of projects with metropolitan overtones was favored to the establishment of a new metropolitan entity. The current majority trend, in response to decades of liberal thought and 20 years of New Regionalism and urban governance, tends to promote vertical and horizontal project-centered coordination in a flexible and fluid manner, embracing private interests and civil society without institutional shackles. Yet, evidence of the operability of flexible forms of governance is not supported by a broad spectrum of empirical data. This article aims to answer two questions: First, is it possible to implement projects necessary for the metropolis without a metropolitan institution? Second, do the projects undertaken strengthen, or help to create, a metropolitan scale of intervention through the emergence of a metropolitan frame of reference?