This article takes the form of a feedback on the setting up of European research projects, unfolding the sequences between objectives, constraints and decision-making for two concrete cases. It shows how the actors of these projects – scholars and engineers – try to elaborate a scientific, documentary, technological and ethical answer to the requirements of the European Commission in terms of research data management, at a time when these requirements do not correspond to professions and practices integrated into the research structures, nor to routines or needs identified among the research teams. It advocates the joint consideration between researchers and engineers of the ethical issues related to data management as soon as projects are set up.