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.
In 1789, before the Revolution the Cathedral Chapter of Sisteron consisted of a Provost, twelve Canons, and twelve beneficiaries (two of whom were curés). They were all abolished by the Civil Constitution of the Clergy in 1790 and by the confiscation of church property. The Canons of Sisteron were officially notified of their suppression on 6 December 1790 by the municipal authorities. The Chapter of the co-cathedral of Forcalquier were similarly notified. Bishop de Bovet was also notified, but he replied that he could not comply since he had no bishop or other competent authority into whose hands he could commit his charge.
On 20 March 1791 the electors of the 'departement' of Basses-Alpes, into which Sisteron had been swept, met at Digne to choose a new bishop. On the third ballot they elected Jean-Baptiste-Romé de Villeneuve, the sixty-four year old curé of Valensole as their Constitutional Bishop. On 2 June he was consecrated in the Cathedral of Nîmes by Constitutional Bishop Roux. By 1795 most of the people had abandoned the Constitutional Church and returned to their old allegiances. Villeneuve died on 23 December 1798 without having reconciled with Rome.
After the Concordat of 1801 agreed to by First Consul Bonaparte and Pope Pius VII, the diocese of Sisteron was not revived and its territory passed to the diocese of Digne.