Catalysis diplomacy, a concept made popular by Brian Hocking, is defined as an association of plural actors (States and civil society representatives, for the main part) interweaving flexible relations around specific aims: it mirrors this trend towards the emergence of the increasingly salient part played by NGOs on the world scene, what Mario Bettati has coined the new spur in international diplomacy. Although it is questioned by some States, this new form of diplomacy seems to be underlying in several normative creations regarding public international law, especially the Rome Status bearing the constitution of the International Penal Court. Indeed, a coalition grouping a thousand NGOs has exercised an action of information towards public opinions, but also certain pressures on governments, in order to render effective the Status signed in 1998; this mobilisation has played an undeniable part in the Status ratification process, elevating to 66 the number of States-parties in 2002. By making the coalition implication explicit, and by evaluating the influence of its main members in the enforcement of this key institution in the field of international penal justice, it is necessary to see in what extent actors in the civil society participate to the creation of international norms in the context of the post Cold War period. – Summary AFRI-2004