The French dairy sectordlike the rest of the economydhas to address the challenge of mitigatinggreenhouse gas (GHG) emissions to curb climate change. Deciding the economically optimal mitigationlevel and mix of abatement strategies requires knowledge on the cost of reducing GHG emissions.Agricultural bio-economic models can help identify which production-system changes are needed toreduce GHG emissions at different levels of incentives at minimal cost. The results reflect the modelstructure and parameter set, especially for GHG emissions accounting. Here abatement strategies andrelated costs for several levels of tax on GHG emissions in French dairy production are compared usingfour bio-economic models: the three supply models AROPAj, ORFEE and FARMDYN and the global partialequilibrium model GLOBIOM. It is found that between 1% and 6% GHG emissions abatement can beachieved at the current price of the EU allowances without substantially reducing milk production oroutsourcing input production such as feed or herd renewal. Cost estimates reflect the planning horizon:mitigation is more expensive when past investments are not amortized. Models that account fordemand-side factors show that a carbon tax has potential negative impacts on consumers through highermilk prices, while these price increases partly offset the reductionsin farm income. Model results suggestthat promising on-farm GHG emissions abatement strategies include measures that let animals reachtheir full production potential and moderately intensive land management.