The text addresses the tension between homogenization and differentiation from the informal and illegal uses of the city. Beyond the condemnations they are subjects, these uses perform essential roles of regulation, both North and South, in economic, urban, social, political. They are forms of valve into the processes of urbanization but also, more generally, of socialization. They allow episodes of retreat or transgression toward the normative context, without calling into question the social order. This logic of yaw/swerve is an analyzer on the tension between normative affiliation and differentiation which innervates socialization. The text explores the dynamics of this tension, as a form of the couple homogenization-differentiation, and its implications into sociology and urbanistic action.