The aim of this study was to investigate the bio-physico-chemical properties of soils developed on dumps originating from lignite extraction and to decipher the respective roles of the geomorphology and the presence of lignite on the biogeochemical characteristics of these soils. Soils from the Armand spoil heap, located in Peypin (Bouches-du-Rhone, France), and natural neighboring Mediterranean soils without lignite were sampled and compared. Lignite presence was assessed by C-13 CPMAS NMR spectroscopy allowing for the quantification of C pools such as aromatic C groups, which are characteristic signature of lignite. Physico-chemical (texture, pH, organic C, carbonate, total N, total S, CEC), mineralogical and biological (enzyme activities: beta-glucosidase, arylsulfatase, acid phosphatase, arylamidase, lipase and fluorescein diacetate hydrolase; Oxitop basal respiration and Biolog (R) catabolic profile) parameters were analyzed in the two types of soil. Microbial activities were higher in the natural soils than in the spoil heap soils, while spoil heap samples exhibited enriched aromatic-C pools. Some variables exhibited a gradient along the slope: carbonate and sand contents were larger at the bottom of the heap while clay content, CEC, organic C and C/N ratio were larger at the top of the heap. On the contrary, microbiological activities did not follow any structured pattern according to the slope and appeared distributed as patches. Variance partitioning combined with multiple linear regressions demonstrated that the C-13 NMR quality of soil organic matter was the main structuring factor of microbial properties, which were in most cases reduced by the presence of lignite.