Purpose: The purpose of this paper is to investigate ways of practicing political power in public space in the interaction between central and marginal users in Glòries, an area under transformation in Barcelona. Originally conceived as the core of its extension, Glòries is now a battle field where conflictive spatial-social manifestations are strongly linked to pending conditions and partially implemented infrastructural projects. The key actors are in large majority illegal migrants, which activities and spatial strategies are particularly uncomfortable for city administrators; challenging the traditional focus on actors that are stable and institutionalized, included and previewed by the tools for urban projects implementation. Design/methodology/approach: To achieve insights on urban spatial articulations of appropriations by marginal actors around infrastructures, the method deployed is to look closely at the interplays between persecuted and persecutors and their ways of practicing power in space in the frame of the illegal street markets in Glòries. This is part of an ongoing PhD research on the complexity of involved processes. The research is executed in diverse work packages: mapping of material transformations (morphology, domain, accessibility and permeability), in diverse timeframes; surrounding functions and temporal fixities, appropriations catalysts; media presences and discussions; crossed references with immersive field work and exchange with locals. Findings: A broad variety of illegal street markets have been monitored in Glòries, revealing an increase in scale, frequency and levels of tension. Around them, their dynamic properties can be extracted and measured: spatial configurations, sizes, timeframes, number of traders/visitors, the relation to other elements, the strategies of displaying, displacing and dispersing used by the police. In all, the relationship with the infrastructural elements shows crucial and a better understanding of their relations constitutes a path to understand how both infrastructures and collective behavior contribute to dynamic productive and power logics in space. Originality/value: This research and case study are an outstanding framework to explore the concrete spatial interactions and interplays of different power or territorialization processes, i.e. the strategies to denote presence and agency – in novel ways. Focusing on their spatial outcomes in contemporary transformation processes where infrastructures are dominant components is a way to inform the design, practice and implementation of city project and management.