During World War II, police officers in Marseille and Algiers relentlessly hunted North African black market operatives. Hundreds of reports from these two cities detail the actions taken to prevent individuals from selling contraband goods, exceeding fixed market prices, or ignoring rationing protocols. In police reports, the figure of the North African profiteer is omnipresent, but internal communication acknowledged that Europeans profited from the black market, too. Why, then, the fixation on North Africans as the key to the black market? In this paper, I argue that police and administrative discourses developed a narrative of Algerians as “internal enemies” of France, a population willing at any moment to undermine the French war effort. In this context, police suspicion that Algerians harbored pro-German sympathies dovetailed with their growing certainty that Algerians were denizens of the black market. In drawing a link between Marseille and Algiers, one a colonial city and the other metropolitan, this paper seeks to demonstrate the importance of Mediterranean networks of knowledge and migration for understanding colonial police practice. With the cosmopolitan, Mediterranean population of Marseille and Algiers, police officers found skin color inadequate to define who was “North African,” instead constructing ideas of race inscribed in language, dress, custom, and, perhaps most importantly, space. Police officers in both cities wove a spatial understanding of black market activity that relied on racialized understandings of urban space. In Marseille, the police efforts to repress the black market focused on Rue des Chapeliers, the heart of Marseille’s North African immigrant neighborhood, while in Algiers, the police scoured the streets of the Casbah. In seeking “anti-French” Algerian black market operatives, the police arrested individuals, but they approached Algerians as a collective threat, targeting neighborhoods the police understood as Algerian. Reading “against the grain” of police reports, this paper explores how the police themselves helped create the imaginary of the Algerian black marketeer and how the tactics police used to control this supposed threat brought them into the lives of ordinary Algerians whose connection to a shadowy black market world was tenuous at best.