Saint-Étienne's cathedral is a neo-Gothic building from the late nineteenth century, consecrated in 1912. It is not one of France's great cathedrals, but it anchors the centre of the city and has some good stained glass. The interior is calm and well proportioned. Free to enter; worth fifteen minutes if you are walking through the town centre.
The cathedral is dedicated to Saint Charles Borromeo, the Counter-Reformation cardinal and Archbishop of Milan — an unusual dedication outside Italy, which reflects the historic church connections of the Loire region.