Instruments of public policy involve more than themselves. They have to go through a political process of drawing up and adopting that shapes their properties, often far from expectations projected on these instruments by economic analysis. The study of international coordination around the climate issue reveals that the choice of an instrument can make the decision regarding how to qualify the situation and choose appropriate normative benchmarks, and then reconfigure the problems of distributive justice to solve. Any linear sequential approach of building an instrumental regime wanted "fair and effective" is so vain. In parallel the failure of the carbon tax in France shows how a "civic" rationale may take up an unfamiliar instrument, as originally designed according to strict "industrial-merchant" concepts, to the point of inducing its abortion. An economic logic focused on cost-effectiveness saw no differences where the fiscal logic saw essential and unjustifiable ones in the name of its civic foundations. Suggestions are made on how to approach this interweaving.
