This sporting facility forms a continuity with the architectural heritage already present on the site of the Saint Nazaire sports centre. Made entirely of raw concrete, with large irregular plate glass windows, the gymnasium symbolises the desire to create generous volumes as a function of their internal use. Despite being an imposing project, it finds lightness in its canted walls and the thickness of the outer shell. Two optical illusions have been created thanks to the variation of the roof tip and the repetition, between shade and light, of the posts that encircle the edifice. A vegetalised roof has been added to create artificial relief, directly modelled in relation to its immediate context. Inside, extensive terraced seating opens onto an exceptionally large playing surface that can accommodate two handball courts, with no load bearing element for more than 2,200 m² of wooden flooring. The roof, with its random perforations, lets natural light into all the playing areas.