This contribution aims to explore the political, economic, and epistemic aspects of the “making of city soils” (Meulemans, 2020) and the role that actors intend for these soils to play in the ecological transition of the urban environment. Informed by observations during meetings between the technical departments of the City of Paris regarding urban soil unsealing policy, these analyses are part of a broader reflection on the emergence of soils as a public environmental problem and how different framings of environmental issues relate to various framings of the “soil” object (Fournil et al., 2018). Each of these framings involves specific discourses on the potential and limitations of soil material transformations, here linked to each city’s department-specific “epistemic culture.”