In the context of climate change, one mitigation technique currently investigated is the use of black carbon (BC) - which is biomass turned into charcoal - t o sequester carbon in soils with the hypothesis that BC is strongly stabilized and will not be biodegraded (or mineralized). In this study, we use the unique opportunity offered by the long term bare fallow (LTBF) experiment of Versailles (INRA, France) to study the dynamics of black carbon at the centennial time scale. Indeed, with no external carbon input and with continuing biodegradation, soil organic matter is depleting. We investigated if BC content was also decreasing at the centennial timescale and compared its depletion with those of other C pools. Our results showed that more than 36% of the initial BC content was gone after 80 years of LTBF (as seen by BPCA technique, Wiedemeier et al ., 20131). This is less than for total organic carbon (66% decrease). BPCA analysis was also carried out on the clay fractions ( < 2 μ m). Results show that BC depletion occurs at the same rate as SOC in these fractions. Our results show that, unlike what is sometimes considered, BC is not strongly stabilized. In th e light of these results, the direct positive impact of BC amendment on soil stocks should be considered with great caution