The health and environment departments of the Departmental Directorates for Health and Social Affairs (DDASS) are consulted for expert opinions regarding the conversion of former industrial sites into urban development projects. The management of these projects involves, in particular, an assessment of the soils at the sites in question and a comparison of the concentrations measured in these soils with those in the surrounding natural environment. In France, there are currently no regulatory standards defining soil quality. Since soil composition depends largely on the composition of the underlying bedrock, a regional reference framework would allow for a more locally appropriate definition of what constitutes a “normal” or “abnormal” concentration for a given element, thereby providing an objective basis for selecting the pollutants included in health risk assessments. This article proposes, for the Île-de-France and Centre regions, threshold values for eight trace metals (cadmium, chromium, copper, mercury, nickel, lead, selenium, and zinc), above which it is recommended to select a pollutant. For each element, the thresholds selected are the 95th percentiles of the distribution of values available in the various databases held by the French National Institute for Agricultural Research (INRA). The soil analyses included in this study come exclusively from agricultural soils (surface horizons). This approach is part of the Ministry of the Environment’s new policy for the management of contaminated sites and soils, in that it provides risk assessors and managers in the regions concerned with a reference condition for soils that approximates “the condition of natural environments adjacent to the investigation area.”