Rapport: The new European Commission has announced policies to reduce greenhouse gas emissions drastically. Reaching an ambitious target for a global good – the climate – would require a common price for carbon worldwide. This however clashes with the free-riding problem. Furthermore, unilateral policies are not efficient since they lead to carbon leakages and distort competitiveness. To tackle these issues, the European Union can rely on different policies. Firstly, a carbon pricing of imports can combined with an export rebate to constitute a ‘complete CBA’ (Carbon Border Adjustment) solution. Alternatively, a simple tariff at the border can compensate for differences in carbon prices between domestic and imported products. A consumption-based carbon taxation can al so be contemplated. Last, a uniform tariff on imports from countries not imposing (equivalent) carbon policies may help solving the free-riding problem.