The circularisation of urban metabolism has appeared as policy objective in cities around the world. But many policies are not “authentically” circular and based on wrong assumptions (Arnsperger and Bourg, 2016). This article prolongs this critical perspective and examines the implications of circularisation for throughput intensity, the spatial structure and socio-technical agencies of metabolistic exchanges. This approach underlines the salience of Political Economy issues that have so far not been addressed in the literature on circular economy. More specifically, we document the existence of cleavages such as pro-growth vs post-growth and technocratic vs emancipatory that are inherent to alternative interpretations of circular economy. Taking into account these issues leads to a more accurate understanding of the social-ecological complexity of urban metabolism, but comes at the cost of lower practical applicability. In order provide operative input to current policy discussions, the complex and mostly idiosyncratic nature of circular metabolism should be addressed in localised, case-specific studies that combine the (mostly quantitative) research on biophysical flows with the (predominantly qualitative) insights on socio-economic transitions.