The French sociology of professions has focused mainly on professional groups organized around a common status, whether it be in the public sector (civil servants) or in private practice ("les cadres"). Yet, another dimension of professionalism has been seldom explored : the fact that professionals belong to "disciplinary communities", sharing the same training and the same expert knowledge. This article draws on an empirical case, the professionalization of psychology in France between 1945 and 1985, to explore the tensions between these two conflicting logics, potentially at work in any professionalization process. The crystallization of this profession into a variety of statuses within the state administration has long hindered a "horizontal" development of the psychological profession, each field of practice trying to advance its own interests through separate professional organizations. The adoption of a law protecting the title ‘psychologist' in 1985 was an attempt to unify the statuses of psychologists in all fields of practice, but eventually failed, since derogatory statuses were granted to certain categories of psychologists employed in the public sector. This situation, however, might change in the future, under the pressure of European regulations that seem to push towards a greater homogeneity within the professions.