Rieben, Henri Keywords: European Coal and Steel Community | Cartels and monopolies | Mots clefs: Communauté européenne du charbon et de l acier | Cartels et monopoles | ABSTRACT In his course, Henri Rieben raises from the outset the two fundamental questions about Western Economic and political leaders in 1956: to what extent did the ECSC constitute the extension and the breaking of the agreements of ironmasters, in particular the International steel agreement? To what extent does the application of the Treaty lead to a goo…