It has been the seat of the Bishop of Saint-Étienne since the foundation of the diocese on 26 December 1970.
The church, dedicated to Saint Charles Borromeo, was constructed between 1912 and 1923 in a primitive neo-Gothic style, on a Latin cross groundplan with transept and triple nave, and a belltower on the west front. The building is 80 metres (260 ft) long, 30 metres (98 ft) wide and 17 metres (56 ft) from the centre of the roof vault to the ground. The organ in the choir dates from 1930, and there is another very imposing one by A. Durand from 1968. The building was however an excessively ambitious one right from the start, and remains unfinished: it was intended that there should be another three belltowers and a dome, besides quantities of external and internal decoration presently lacking.