To date, the majority of the research on microplastics (MP) has focused on the marine environment. The pollution of continental ecosystems is comparatively little studied, even though the majority of all plastics is used and disposed on land. Recent studies on soil contamination by plastics and microplastics have revealed the presence of plastic particles in various terrestrial ecosystems, from the most urbanized and industrialized areas to the most remote areas. The main sources of plastic in soils include land application of contaminated sewage sludge and compost, plastic mulching, wastewater irrigation, atmospheric deposition, littering and surface runoff [1]. However, estimates of MP concentrations and chemical natures are still limited and differ between studies. In France, only a few studies have tackled the issue of MP contamination in soils. The MicroSof projects aims to establish first national references on the contamination of French soils by microplastics. To do so, soil samples from 42 different sites under different land uses will be analyzed. A protocol for the extraction and characterization of MP is currently being set up. After pre-treatment and subsampling, the samples will be digested with Fenton's reagent following the methodology outlined by Hurley et al. (2018) [2] and MP will be extracted by density separation. The study will then allow to quantify (mass, number) and to qualify (chemical nature) the accumulated plastic fragments, as well as the size and the shape of these fragments. [1] M. Bläsing et W. Amelung, « Plastics in soil: Analytical methods and possible sources », Science of The Total Environment, vol. 612, p. 422‑435, janv. 2018, doi: 10.1016/j.scitotenv.2017.08.086. [2] R. R. Hurley, A. L. Lusher, M. Olsen, et L. Nizzetto, « Validation of a Method for Extracting Microplastics from Complex, Organic-Rich, Environmental Matrices », Environ. Sci. Technol., vol. 52, no 13, p. 7409‑7417, juill. 2018, doi: 10.1021/acs.est.8b01517.