FRANCE. Provence-Alpes-Côte d'Azur region. Var department. Ollioules. Châteauvallon festival "Musique ouverte" first edition. In the background, from left to right : Swiss jazz musician Léon FRANCIOLI (double bass) and French jazz musician Bernard "Beb" GUERIN (double bass). In the foreground, a back view of French jazz musician Michel PORTAL (clarinets, saxophones, bandoneon). Rehearsal backstage for the concert on Monday, August 23rd. MICHEL PORTAL UNIT. Sunday, August 22nd 1976.