This paper analyzes three specific aspects of this relationship: establishing the economic context, the public/private actors and their respective spheres of action are underlined. One can wonder if there an European model in planning? The two fold typology of urban planning systems (Continental and Anglo-Saxon) pleads for the recognition that there are indeed two models in planning : the Continental planning and the Anglo- Saxon way of planning. Another set of questions presented here : are there any contradictions among the two planning systems or are they rather complementary in a diversified European context? Assessing the systems at work implies an analysis of each system's results which are based on the ability (or not) to achieve the stated goals during the implementation phase.