Inspired by Deleuze and Guattari’s philosophy of becoming, as well as by Spinoza’s ethics, this article advocates that planning be apprehended as a transitory construct to deal with social processes, which are inherently unpredictable, and to enact a justice that is ontologically spatial and amoral. This idea stems from conceiving of reality as the relentless encounters of bodies (assemblages) whose fight for space determines unique temporary agreements (spatial justice) as a result of power exchanges (affects) among these bodies – and of their stabilisation and escape movements, of course. This approach aims to overcome conceptualisations of justice that focus primarily on superstructural causes of injustice or on ready-made normative solutions. Although widely accepted by scholars in fields such as geography or planning research, these conceptualisations are still unable to account for the increasing incidence of social inequality our cities face. A case study, drawing on the fight for space among women in prostitution in a historic Genoa, Italy, neighbourhood, will serve as a translation from theory into practice.