Cooperation between stakeholders is becoming a major challenge for the development of corporate social responsibility [ISO 26000] and eco-innovation approaches. Indeed, eco-innovations (eg Dyson Airblade, the Velo'v, cosmetics, Lush, AMAP ...) often cause the emergence of new forms of organizations that involve the creation of a new network of heterogeneous actors, outside the traditional ecosystem. The development of such innovations questions the actors, their roles, theirs values, their performances and their ability to cooperate in a long-term project. We are interested in decision-making tools to facilitate the maturation of eco-innovative project. We seek (1) to avoid the dilution effects of environmental and social values and (2) bring systems of stakeholders towards more responsible behaviour. In this article, we propose a model to assess the stakeholder system (SS) and to analyse its evolution during the maturation of an eco-innovation. The SS model is discussed and completed by the EVOLO case study, a company specialised on urban mobility.