The use of contaminated soils for non-alimentary cultures is gaining importance in view of the scarcity of agricultural surfaces and the presence of some potential harmful pollutants in surface horizons that could impact the food chain. But in the case of trace metal contaminated soils few information are available on the effects of land use and soil management changes on soil quality parameters and/or soil health. Suggestion was made in literature that enzymatic activities could be good indictors of soil functioning, providing special attention to confounding effects. In this work the objective was to assess the impact of change of cultural practices on the soil quality, as seen by soil enzyme activities. Materials and methods We used trial essays were contaminated parcels were divided in two, one part was left under annual culture and the other was planted with the high biomass plant Miscanthus giganteus. The enzymatic activities of the C and N cycle were investigated with a diachronic follow-up of β-glucosidase and urease activities, quantified on fresh soil triplicates using colorimetric methods and microplate assay. The effect of miscanthus plantation was also followed up in a soil profile. Soil samples were collected in spring from 2009 to 2011 at 0-10 cm in a trace metal contaminated site with an organic origin of pollution. Sampling in the soil profile was done every 10 cm in depth until 50 cm. Results Results for the diachronic follow up in surface horizons showed that soil urease activities under miscanthus differ clearly from those under annual culture with higher values under perennial culture. This was particularly observed as the setting-up of miscanthus was former. β-Glucosidase activities, while less indicative, also suggested an enhancement of microbial activities under miscanthus. When normalizing with the enzymatic activities of the parcel under annual culture, results clearly show the effect of the plantation duration on the re-functionalization of the soil. But despite the rapid answer of the indicators, three years were necessary to significantly quantify an evolution. N cycle was more sensible to point out the re-functionalization of the contaminated soil. In the soil profile results of the enzymatic activities under miscanthus highlighted the evolutionary structuration of microorganisms in contaminated soil. This evolution was faster near the soil surface than in subsurface horizons and better assessed for N cycle.