This research aims to address two gaps. The first is related to a lack of theoretical and practical research on urban commoning processes understood as 'practices', that is. as "embodied, materially mediated arrays of human activity centrally organised around shared practical understandings" (Schatzki et al., 2001, p. 3). The systematisation of such 'knowledge-in-practice' (Schön, 1985) aims to form a 'meso level' between the more abstract 'macro' theories that consider the city in itself as a commons (Harvey, 2012; Hard & Negri, 2009; Stavrides, 2016; Foster & Iaione, 2018) and the concrete 'micro' experiences looking at independent and autonomous spaces such as housing cooperatives, urban gardens or timebanks (Ferguson, 2014; Gruber et al., 2018; Dellenbaugh et al., Pelger et al., 2017). This effort complements the work of scholars interested in commons as social organisations (De Angelis, 2017) or in the conditions for their replicability (Baibarac & Petrescu, 2019). The second gap concerns the lack of studies on the practical articulation between the concept of urban commons and municipalism. In this regard, the research addresses different scales and territories: from the Spanish municipalist 'Cities of Change' and the local policies develope, to specific processes in Barcelona involved in processes of commons-based governance reflects, and how they resonate and influence other European cities such as Belgrade or Berlin. The reserach applies an activist research methodology that is “grounded in a commitment to the augmentation and transformation of the movements” in whic the researcher takes part (Russell, 2015). In this project, the ‘movement’ is not an ‘organised collective of people’ (Hale, 2001) but a network of practitioners working on the articulation of urban commons within emerging new political projects. The usefulness of the research will be defined and tested by these practices during the study.