Cette these porte sur une analyse de politique publique dans un champ d'action internationale, la cooperation au developpement. l'etude s'interesse particulierement au cas de la construction de la politique communautaire de cooperation au developpement, et de son affirmation visa- vis des politiques nationales europeennes. pour ce faire, cette these analyse d'un point de vue qualitatif les ressorts de l'action de l'union europeenne, a la fois pour penser le developpement dans la caraïbe, et pour penser et faire l'europe. de l'autonomisation d'une politique a l'harmonisation des politiques nationales par le bas, c'est une veritable recomposition du systeme d'acteurs qui s'opere. ce renforcement de l'integration europeenne, dans un domaine d'action partage, par le biais d'outils renouveles de l'action publique, dessine alors progressivement les premices et les contours du cadre legislatif qui a ete mis en place par le traite de lisbonne en 2009 / This dissertation analyses a public policy in an international field of action: the development cooperation. the study focuses in particular on the emergence of the european community policy of development cooperation and its assertion towards european national policies. using a qualitative methodology, this research aims to improve the understanding of the motivation and the processes at stake within the european union. the field analysis has led to observe both how the development policy in the caribbean ras been thought and built, and how this process may rave an impact on the european integration process itself. from the empowerment of a policy to the harmonisation of national policies, this process carries also consequences on the system of actors, which ras been reconstructed by those changes. as a result, the european integration process has been strengthened in a field where the competence is generally shared between the eu and its member states. bringing out some new or renewed tools of public action, this outlines also some of the signs or provisions of the forthcoming legal and political framework, set up by the 2009 lisbon treaty