[en] The European Community directive no 2003/87/CE aims at fighting against climatic change by the implementation of a greenhouse gas emissions trading system. This architecture has been precised in the European Regulation no 2216/2004 relative to the normalized and secured registers system. This document describes the principles of Powernext Carbon, the quotas trading market, launched by Powernext in partnership with Caisse des Depots and Euronext: context, size of the European CO₂ market, regulatory situation, Powernext Carbon - the European CO₂ quotas stock exchange (partnership, architecture, spot products, European members network), theory and practice of Powernext Carbon continuous market (reference electronic platform, 3-step negotiation, invoicing and added value tax, tariffing. (J.S.)