Species choice is potentially an important management decision for increasing carbon stocks in forest ecosystems. The substitution of a slow-growing hardwood species (Quercus petraea) by a fast-growing conifer plantation (Pinus nigra subsp. laricio) was studied in central France. Simulations of carbon stocks in tree biomass were conducted using stand growth models Fagace´es for sessile oak and PNL for Corsican pine. The changes in soil carbon were assessed using the Century model and data from two European soil monitoring networks: 16 km _ 16 km grid and RENECOFOR. Carbon in wood products was assessed with life cycle analysis and lifespan of final products. However, only carbon stocks and their variation were accounted for: effects of energy-consuming materials or fossil fuel substitution are excluded from the analysis. To compare the growth of these two types of forest stands, an important part of the study was to assess the productivity of both species at the same site, using National Forest Inventory data. Simulations showed that (i) this species substitution would lead to an additional carbon storage of 1.6 tC/ha/year with the conifer plantation during its first rotation (64 years) (ii) at steady state, the timeaveraged carbon stock of the conifer plantation over the whole rotation would be 42 tC/ha to 47 tC/ha lower than that of the hardwood even-aged forest, depending on applied silvicultural scenarios. The time-averaged carbon stocks including vegetation, soil and wood products are 221 tC/ha for sessile oak, and around 175 tC/ha for Corsican pine. The amount of carbon stored in wood products is low compared to the total carbon stock (5% for sessile oak, 88.5% for Corsican pine), mainly due to important losses during early wood processing, and to the short lifespan of wood products compared to the rotation length of forest stands.