You needn't have a strong religious faith to appreciate the calming atmosphere of Saint Claude Cathedral. Ask when the next service starts or when you can go for a wander through.
This Saint-Claude principal church is an ideal place to begin your day of sightseeing. There's plenty to see in the vicinity, such as Flumen Waterfalls, Musee des Papiers, and Saint-Claude Golf. Take your time at Saint Claude Cathedral before hitting up these other fine sights.