In the changing history of city-river relationships, cities are today questioning strategies for “reconciliation”. Thus, rather degraded sites like riverside brownfields represent an important potential for the creation of new sustainable fluvio-neighborhoods. This research project focuses on the Rhône, and aims at developing an integrative strategy facilitating decision-making for rhodanian neighborhoods in transition. This paper presents the methodology of the research, which is composed of three work packages: 1-a research by design approach, 2-a decision-making support, and 3- interactions with stakeholders. Thanks to the “research by design” approach, several project-based visions developed on 4 selected study sites along the Rhône form the material for the elaboration of the decision-making support. The latter consists of two separate but correlated elements: a sustainability profiler, and an analysis framework for the new city-river balances. It is enriched by inputs from different stakeholders.