Résumé : Most papers propose extended producer responsibility (EPR) as an incentive for the future development of cleaner production processes. In this paper, we propose an EPR calculation method as an instrument to collect funds to offset past environmental degradations that occurred before environmental legislations were enforced. However, often an unfortunate side effect of EPR is the legal disputes over who should be considered liable. To solve that problem, we suggest a scientifically rigorous method that identifies liable economic agents and calculates the apportionment of restoration costs between producers responsible for direct environmental degradations and their intermediate and final consumers responsible for indirect degradations. We apply our method to the case of fish nurseries – a marine habitat – that have been continually destroyed by industrial harbours since the industrial revolution in the Seine estuary (France). Our EPR calculation method should diminish losses of profit per polluter caused by the restoration costs. Such diminution is expected to reduce lobby pressures responsible for lower environmental targets in environmental legislations. EPR is also expected to preserve harbor activities that contribute to the general interest and generate a positive externality for climate change mitigation, justifying restoration costs to be borne by a larger number of sectors than harbours alone. In the EPR restoration scenario involving polluters, users, users of users and final consumers, profit losses for the main destructors of habitats – harbours and the mining sector – reaches 12.6% and 6.3% respectively. For the other sectors, profit losses do not exceed 3.4% (estimated with an input-output model).