Within the framework of policies aiming to reduce greenhouse gas emissions, France now relies largely on energy substitution. This results in the implementation of projects involving fuelwood or heat production from biomass. On the other hand, due to the very partial consideration of in-situ sequestration in the international climate policies ensuing from the Kyoto treaty, State action hitherto has not relied on measures favouring forest carbon sequestration. Some researchers from the Nancy Laboratory of Forest Economics developed the French Forest Sector Model (FFSM), a bio-economic model of the French forest-wood sector, used for simulations of climate policies and impact analysis. The first results of the FFSM model show that: (i) an ambitious policy of substitution may cause tensions on resources and wood industry markets; (2) a sequestration policy presents a better carbon balance through to 2020 than a substitution policy; (iii) the implementation of a generalized carbon tax would have a globally positive effect on the French forest-wood sector.