Tackling societal and grand challenges requires the collaboration of multiple organizations and actors on a common issue to innovate, which can take the form of so-called ‘governance’ policies. In the context of collaborative public innovation, governance experiments have become widespread, but are subject to tensions in relation to the articulation between local implementation and wider diffusion and to the articulation of the tight project time with processes of collective action. Drawing on a post-analysis of a major experiment in France to prevent ‘avoidable’ hospitalizations of frail elderly people, this paper proposes to shed a new light on governance experiment as ‘dispositive implementing’, articulating the theoretical notion of the Foucaldian dispositive in organization studies with process studies. Through the analyse of the ‘dispositive implementing’ of a platform that aims to be a single desk to better coordinate elderly care pathways between health and social professionals, the research highlights the variety of elements in the dispositive and that the intensity of the links between them comes from physical aspects, such as co-location, strategic discourse, but cannot be achieved without frequent and close management combining bilateral and collective relations. It also suggests moving away from the dichotomy between design and implementation in experiments towards a more continuous process of concretisation.