In Western states, restrictive migration policies over the last 30 years have entailed a shift in the practices of control, leading to the institution of systems of detention at international borders. Border confinement raises substantial issues about fundamental rights; it involves questions of legality and legitimacy, and the definition of new technologies of government. In France, the origins of border detention show how pre-existing administrative practices of detention were legalized through the adoption of “waiting zones,” a new regime of detention that enhanced both conditions of detention and disciplinary control over detainees. This development confronts human-rights activists who have opposed border detention since the mid-1970s with “paradoxical gains” and a tough dilemma: the rights that have been granted by the state to travellers held at the borders are not enough, whereas legalization has opened the way for new control mechanisms. Understanding border confinement involves analysing these paradoxes produced by constant negotiations between the administration, willing to tighten control over its borders, and concerns of certain groups within civil society, willing to defend basic rights and give a legal framework to control practices. In France, the diffusion of penitentiary models of management and the ambiguities of law that this article explores further draw together the conditions for administrative processes of legal exclusion. What do such processes teach us about evolving regimes of government within rights-based liberal systems?