A good share of tourists never wander beyond the front plaza, interior or bell tower. Walk behind the cathedral to Square Jean XXIII for a little tranquility. Shaded benches will be your friend and the view of the flying buttresses and gothic Fountain of the Virgin will entertain your camera.
A little known fact: not far, on the roof of the sacristy is a specially placed bee hive. From ND’s website: “Notre-Dame de Paris, accommodating this hive, matches the preservation of the dynamic biodiversity and hopes to remember the beauty of creation and the responsibility of Man towards her.” Wow! This hive belongs to beekeeper Nicolas Géant who disposes many hives on the roofs of Paris. Bees of this hive are the gentle Brother Adam variety, an essential virtue for urban beekeeping.