An increasing number of scholars consider Circular Economy as an effective approach to deal with environmental challenges and value creation and achieve a transition towards sustainability. But while many researchers have studied the countless challenges faced by organizations trying to implement Circular Economy, few of them have been interested in the potential role of public procurement to foster its implementation. Yet, management literature has already stressed that public procurement can be an effective policy instrument to advance the transition towards sustainability (Aldenius & Khan, 2017). Consequently, the question we raise in this paper is to determine under which conditions public procurement can represent an effective instrument to accelerate the transition towards Circular Economy. In order to deal with this question, we use a qualitative method focusing on a research project which aims at developing Circular Economy in Paris Region using public procurement. Drawing on results coming from transition studies (Geels, 2002; Geels & Schot, 2007), our research conceptualizes a multi-level approach which outline the required conditions to achieve the implementation of an effective circular public procurement.