The former French diocese of Sisteron existed until the French Revolution. Its see was at Sisteron in southern France and at Forcalquier, in the modern department of Alpes-de-Haute-Provence. Sisteron was the only diocese in France which had two cathedrals. Each cathedral had a Chapter, and the two Chapters voted together when an election was held to elect a new bishop of Sisteron. The diocese of Sisteron was part of the ecclesiastical province of Narbonensis Secunda, whose Metropolitan was the Archbishop of Aix-en-Provence.