Purpose In urban areas, soil functions are deeply impacted by all human activities, e.g., water infiltration, carbon storage, and chemical substances degradation potential. In this context, nature-based solutions (NBS) are assumed to deliver multiple environmental benefits for soil quality improvement. The H2020 Nature4Cities project (N4C) offers the framework to develop physical, chemical, and microbiological indicators to the performance assessment for addressing NBS soil quality (performance assessment of soil quality) to be included in a toolbox designed for architects or municipalities. Materials and methods A simplified performance assessment methodology was developed for addressing NBS soil quality. It is based on the comparison of physical, chemical, and biological characteristics to soil reference baseline. In this setting, we present here the results obtained from case studies selected in three European cities (Nantes (F), Nancy (F), Bustehrad (CR)) to test the methodology. The case studies correspond to three different NBSs: former market turned into gardening areas (FMG), green roofs (GR), and urban allotment gardens (UAG). The performance assessment was based on two criteria: (1) soil fertility and (2) soil contamination. Results and discussion The basic soil properties (e.g., pH, bulk density) and soil fertility (e.g., soil organic matter (SOM)) for the two open soil NBS (FMG and UAGs) are equivalent to cultivated soils. Those of GR are highly controlled by the type of natural materials used in the substrate. Concerning contamination, the soil quality of FMG was shown to be significantly impacted by former agricultural practices (pesticide residues, trace metals (TE)). Measured molecular biomass of FMG was compared with