The DE.SO agency (urban architects based in Paris and Avignon) responded well beyond the client’s expectations with Opéra Confluence, a fully reusable ephemeral room which, today, has demonstrates the consistency between its envelope and acoustics. The optimal conditions for lyrical and diversified performances as well as the comfort of artists and spectators are proven. This project is part of a circular logic from the outset, as evidenced by the use of recovered equipment (armchairs, stage, grill) and the building’s vast potential for reuse. In fact, the glulam frame as well as the entire envelope made up of prefabricated boxes (and technical and scenographic elements) are completely removable and reassembled. The reduced number of assemblies enables the main structure to be lifted and built in a fortnight. The Opéra Confluence is revealed inside. Contrasting with the inert metal cladding on the facade, the wood is multiplied in structural elements, finishing panels and acoustic elements. Through its smell, color, tone and touch, the material creates a protective and warm environment. The general design of the Opéra Confluence makes it possible to dissociate or combine each technical and programmatic element to envisage multiple future uses; the wood used for the structure and component of the casing is easy to handle, combine and possibly modify. This construction system offers a multitude of possibilities for using the building, its “low tech” character open to any capacity to appropriate a local identity.Now that the historic Avignon Opera is resuming its natural rights, the Opera Confluence is looking for a place to welcome. It will then have achieved its objective of an ephemeral and sustainable Opera, a theater outside the walls perfectly suited, as in Avignon, to ensure the continuity of high-level cultural services.