Smart mobility, smart cities, smart home, autonomous driving, etc. Energy and digital disruptions promise seamless customer experiences which integrate several products & services. Private companies and public authorities invest to push forward collaborative projects in these fuzzy, but promising areas. Companies like Tesla or Bolloré integrate this radical shift in one single company, investing billions with a very uncertain direct profitability. Regular players see the same challenges and have to collaborate to make their current products scale up to these future concepts, far from their core business. We bridge “innovation management” and “ecosystem” literature to define the notion of “proto-ecosystem project”, highlighting the way various players co-construct offers and assets in a joint systemic and ambitious project. We use this framework to analyze two projects we took part to, involving several industrial and public players, who invested several millions of euros on “electric infrastructures” (case 1) and “data marketplace” (case 2). Results indicate that such “proto-ecosystem projects” are both critical and deceptive for each player. We explain this paradox showing that partners need such ecosystem projects to go forward and update their competences and roadmaps; but at the same time the dominant focus on “sticking collectively to the initial business plan” tends to disconnect the project management from the rich learning made together and from the evolution of the agenda of each partner. We conclude by positioning the concept of proto-ecosystem as an intermediary “management object” for innovation management, and pointing several implications to manage such projects with more flexibility in order to allow partners to gain competitive advantages.