Notre-Dame-de-la-Sède Cathedral (French: Cathédrale Notre-Dame-de-la-Sède de Saint-Lizier) is one of two former co-cathedrals of the town of Saint-Lizier in southern France. The other is the Saint-Lizier Cathedral. The town of Saint-Lizier was formerly the seat of the Bishop of Couserans. The diocese was abolished under civil constitution of the clergy in 1790, and this was confirmed by the Concordat of 1801.