The aim of this article is to analyze the power of trade unions to influence a French industrial policy. The study examines the case of the medical imaging industry, in which a trade union managed to convince both the firms and the government to invest in a new innovation center. Through a qualitative study, the author highlights step by step the power resources this trade union used to deploy multi-level ‘political work’. Through this lobbying process involving various actors, resources and institutions, the study examines participation of stakeholders in industrial policy formulation and implementation, questioning the possibilities for a trade union to be decisive in economic development. It is found that the lack of trade union structural power and institutional power (including investment capabilities) makes it difficult to successfully put an industrial project on the agenda and even more difficult to participate in the investment phase.