More and more management research use fiction as an insightful way to analyze complex organizational dynamics. Focusing on user appropriation of Knowledge Management Systems, we investigate how Astérix was used to understand the KMS appropriation process in a large French firm. Based on the notion that culture is central to appropriation, we argue that Astérix can be considered as a cultural metaphor able to address issues associated with KMS appropriation in this French context. We use this metaphor in an action research project designed to help managers address knowledge management problems in order to support appropriation and use. These results contribute knowledge in three different areas. First, we underline the role of cultural metaphors in information systems appropriation. Second, we enrich the literature on the role of fiction in management by illustrating the role of cultural metaphors. Third, we report on how this can be used in an action research project with the potential of leading to practical managerial suggestions to understand better KMS appropriation issues.