Five hours in Paris

A stroll through the Latin Quarter just across the river would be a very nice activity before or after visiting ND.

ETA: This was my 666th post on this forum. MWHAHAHA!!!!

It is a short walk from Notre Dame to I’le St-Louis, original site of Paris, charming.

Rick Steves has an audio guide "Historic Paris Walk" that takes 4 hours and begins at Notre Dame. https://www.ricksteves.com/watch-read-listen/audio/audio-tours/paris

The Rick Steves' walk recommended by Marty is an excellent way to see some highlights. You may not have time to go into everything (depending on lines) but you will see some iconic sights.

Donna - Do you know exactly where you will be dropped off in Paris?

I wish I knew! The website only says the drop off is in a "central location." I'm trying to find a review that might give me a hint.

Don't be discouraged if you see a long line snaking out the front doors of Notre Dame. It moves very quickly and the slowdown is just for security. Really, it is usually 10 minutes at most.

Also watch your purse (Keep it close and in front of you with your hand on the zipper) in this area as the petition girls work the line trying to get people to sign a bogus petition then demand money. Don't respond to their Do you speak English queries and ignore the ones that make motions that they are deaf and mute. They are not. Just ignore them without making eye contact. This sounds horribly negative but I've sat on the walls around there and watched them work the unsuspecting.

Have some Euro coins with you as there is a public restroom on the plaza area downstairs by the statue but you'll need coins to get in.

After you spend time in Notre Dame, I, too would follow Rick's Historic Paris walk in the reverse. I'd go down the side street that is at right angles to the front door of ND and pick up a sandwich (I like the shop Hure), then do the walk and picnic on the Square du Vert-Galant if the day is pretty. Something like this:

https://goo.gl/maps/EHRvq1YnTn92

The line at Notre Dame moves quickly. That won't be true everywhere else. You can also get into the archaeological crypt (across the square in front of Notre Dame) easily but that doesn't seem to interest everyone.

From there, you have options:

You can stay on the island and probably have time to wait in line to see Sainte Chappelle and/or Conciergerie.

You can walk to Luxembourg Gardens and visit the Pantheon. There is also Arenes de Lutece, an old Roman amphitheater with a small surrounding park. It's interesting but used mostly as a place for Parisians to eat their lunch (most workers stop for a to go sandwich, at any bakery - boulangerie - or deli - charcuterie - and walk to a nearby park).

You could also walk down river on the right bank to see the Louvre (possibly a really long line). If you pick a wing that isn't one of the main draws, the crowds inside can seem small. If the line at the Louvre is too long, you can keep walking to the Tuileries garden. At the end of the garden on the left is the Orangerie, where they have a couple oval rooms of Monet's water lillies. I've had good luck with lines there. Pretty much directly across the river from there is the Orsay museum (again maybe too long of line). It's a great art gallery.

If you add the metro, you could go up to see the Arc de Triomphe or Eiffel Tower.

There are a lot of possibilities but not enough time to pick more than one or two things depending on lines.

You stated "... website only says the drop off is in a "central location.". Depending on traffic, time, and other considerations, it may or may not be the same place each cruise. Perhaps you can find a review on cruisecritic.com Or perhaps you can contact the shore excursions department by phone or email and get an idea of at least the general location of the drop off and pick up points.

Very near Notre Dame there is a small but moving monument to the Holocaust. I'd go there then do the Rick Steves walk.
If by any lucky chance your cruise stops on a Sunday, go to mass, whether or not you are Christian, whether or not you speak French. You see the church doing its job, what it was built for, and there are not people milling around talking loudly in the language of your non choice.