This article seeks to grasp the evolution of French border management policies over a half century (1953-2004) from the vantage point of one specific activity performed by border police (PAF): the collection and use of information from border checks. This form of knowledge production represents a privileged object of analysis by which to observe the professional developments of this police department. The PAF was first an intelligence police department and then a police service dedicated to immigration control in the 1970s, before finally becoming a department in charge of the fight against migration-related crime from the 1990s. Since the 2000s, the PAF now cooperates with the European agency Frontex. In turn, the definition of administrative categories and analytical tools used by the PAF have equally followed such institutional transformations towards the criminalization of immigration and the Europeanisation of border control.