The building is sited behind the National Museum of History and Archaeology and offers fine views over the port's cranes from its bay windows. It houses a Roman mosaic found in 1959, vestige of the terrace of a huge commercial complex (market and warehouse) built in the 4C as the nexus between town and port. Its 800m2 is covered in geometric and organic motifs. Below stood baths dating from the same period (4C-6C), the structure of which is still discernible.