You'll probably see Montauban Cathedral from a distance before you actually find this amazing building. Peek inside if the doors are open or just admire the facade from outside.
You'll have sightseeing choices galore when visiting Montauban. Montauban Cathedral is an ideal place to begin here, but there are numerous other fine spots to enjoy. Place Nationale, Ingres Museum, and Jardin des Plantes are close to the principal church and and will cap off your day nicely.