This article considers the techniques of tele-action and their (non) use by technicians responsible for supervising telecommunication networks at France Telecom. The authors examine the fact that tele-action is one of the most recent, innovative and powerful techniques ever made available to the technicians concerned and yet, paradoxically, also one of those that they use least. They investigate this paradox that seems to run counter to one of the key findings of the sociology of organizations, i.e. experts' propensity to use their field of competence and their sphere of control to maintain or strengthen their position. This paradox is based on a dilemma: although tele-action expands technicians' competencies it also gives them the means to interfere with the action of colleagues with whom they identify. The article then shows that this conflict between capacity for action and solidarity between technicians is the cause of a reserved attitude towards colleagues and caution as regards management - an attitude that seems to undermine the individualization of professional projects and certain technicians' adhesion to new technologies.