The origine of this project is an artistic commission of Les Nouveaux Commanditaires. El Gran Trueque* is the first project and took place in Santiago. Thanks to the collaboration of "Un Techo para Chile", the action of Les Nouveaux Commanditaires has crossed the rehabilitation program of a district of the municipality of Lo Espejo, so that the people living there in a camp could benefit from a permanent installation. The artistic commission found itself implemented in a context of great material precariousness which was a key parameter in the design of the project. It is the analysis of the needs and of the living conditions in the camp that led to the idea of a participatory mode of operation, in adequacy with the environment and the artistic process. The first step of the project took the form of a workshop, "el taller de los deseos" which allowed the community members to make the objects they desired by collecting wood and other materials. Each participant made a full-scale sculpture representing an object. Then the sculpture was stamped with a buffer indicating "El Gran Trueque, Nicolas Floc'h and the name of the person who made it". These artworks, co-signed, were presented as part of the personal exhibition of Nicolas Floc'h at Art Center Matucana 100, Santiago, Chile, thus fully integrating the institutional art network. During the exhibition the objects could be traded : a person could acquire the sculpture of her choice in exchange for the real object it represented. Then, the real object was given to the person who had made the corresponding sculpture.