Tulle Cathedral, formally Cathédrale Notre-Dame de Tulle, is the town's main landmark and the best place to start. The building is restrained rather than flamboyant, with Gothic lines that suit the narrow valley setting. Inside, look for the stained glass in the choir and the organ, then step out into the cloister.
The cloister is the part that lingers in the memory. It belonged to the old Benedictine monastery and keeps a small gardened calm just off the town streets. It is not a grand Loire-style showpiece, but in Tulle that is part of the appeal: stone, shade, and a very local sense of history.