In this article we present SenPeer, a new Peer-to-Peer data management system allowing data sharing among experts working on the development of the Senegal river in a decentralized and lexible fashion. SenPeer has a Super-Peer network topology based on an organization of peers in semantic domains and in which peers can contribute XML documents, relational or object databases. Each peer exports its data in a common formalism which has a graph structure semantically enriched with a set of keywords in order to guide mappings discovery. Mappings discovery relies on a set of fuzzy similarity measures. Moreover they allow the establishement of a semantic topology that is independent of the underlying network topology which is the basis for intelligent query routing.