Abstract : This research takes the literature on management tools (Moisdon et al., 1997 ; Hatchuel et Weil, 1992 ; David, 1996, 1998) as a starting point. I focus on the co-evolution of a management practice in-use (Jarzabkowski, 2004), here Knowledge Management (KM) and an organisation. My research deals with the question « How can we do KM ? ». This refers to the different approaches for managing knowledge as well as to the different reasons that lead an organisation to adopt KM practices and tools. A multi-level analysis, combining the institutional, organisational and inter-individual contexts, is carried out. This framework calls upon various theories: institutionalism, management tools, managerial theories of the multinational corporation, social regulation (Reynaud, 1989), thus broadening our understanding of the dynamics of a management practice in-use within an organisation. The concept of emplotment (Ricoeur, 1983) is used to study the dynamics of KM within the Cement Division of the Lafarge group. The main plot - why KM? - brings forward the strategic context of the cement industry and the organisation of the technical expertise function. This plot is the starting-point for the different stories of KM in the Cement Division, which are told from different perspectives in time and space. The main results of this research show that Knowledge Management is mainly used to increase the firm's legitimacy both towards external and internal stakeholders. KM is a tool in the hands of strong headquarters that claim to be the ultimate knowledge owner. Thus, I related the switch of KM from a perspective based on personalisation, competencies management and autonomy to a perspective focusing on codification, information management and prescription. Resistance to codification highlights the conflict between KM, set in a control mode (régulation de contrôle) and the employee's will for autonomy (régulation autonome). The tension between these two types of regulation leads to a crisis as can be seen through the growing sense of unease among the experts. In the end however, such tensions do not interfere with the daily run of operations as KM is decoupled from ongoing activity. Thus, the story of the Cement Division is a case of strategic domination. In the absence of a joint regulation (régulation conjointe), decoupling discourse from practice allows the survival of the organizational model.