He's No Stair-Climbing Fool...

I'm not certain about the bell tower of Notre Dame, but the Arc de Triomphe has a separate set of stairs for entrance and exit. I last visited several years ago, so my memory may not be perfect, but I seem to recall that the spiral staircases involved are rather narrow. I think it would cause significant problems with the flow of people traffic through the monument if you needed to step aside and descend back down.

I am a physical therapist who specializes in vestibular dysfunction...issues related to the inner ear. Plus i have vestibular hypofunction, so I am prone to motion sensitivity and dizziness. I do not think you will have an issue clmbing up the spiral staircase of Notre Dame. I will most likely be when you are climbing down. What I found to help me get down the spiraling staircase was to ignore all those around me and count each step as I walk down. It gives me a sense of cadence and gives me a clue as to when to make my next step. If I am distracted, I would mis-step......an issue that will be ok, as long as you can hold onto the rail or run your fingers against the wall. As far as being on top of the tower, stay close to the building.....look out, but dont get close enough to look down, because that is when you may freak out. I did not have a problem up top on Notre Dame looking down but did on the tower in Ghent, a tower that wasn't even as tall as Notre Dame. I stayed close to the building and didn't have an issue.
Got any tall buildings near your home? Get on them and try it out. Bonus if any of them are spiraling.

Quite frankly, I'd suggest you skip it. Not the trip, just the extra stairs. You're going to be going up and down more stairs than you expect. Every cafe will have the restroom either up or down stairs. Lots of stairs in the Metro, even when there's an escalator at the main entrance. But those you can take at your own pace without worrying about blocking all those tourists. I can't tell you if the view from either is worth the effort. I chose to feel better for the rest of my trip rather than attempt it. Especially with the vertigo, you don't want to be like Jimmy Stewart, clutching at the stairs in Notre Dame! Doesn't the Arc have an elevator for handicapped use?

Of course you shouldn't cancel the trip, but if you believe the stairs will be an issue let your bride go up and just wait at the bottom for her. She can take the photos and you can save yourself for all the other stairs you will have to contend with in Paris. I have a knee that gives me problems from time to time and that is how my husband and I handle that situation.

You can take an elevator up the Arc de Triomphe...so no problem there, there is a set of stairs after the elevator stops , but that sounds like it would be no problem for you ( think its like 20 stairs) The Tower of Notre Dame is just a NO! The stairs on ONE WAY , steep, narrow . Turning around not really an option.
However she will descent almost where you go in, so no problem letting her go up on her own. Suggest you just take a seat at an overpriced cafe across street and wait, she will be about 1/2 hr anyways( after being admitted, line could be much much longer, please go BEFORE it opens to get at start of line) .Sure coffee at a cafe there will cost you 4-5 euros, but you can sit there as long as you like ,people watch , and she can find you very very easily.

The Arc has 369 steps and the view was terrific. We later learned that it does have an elevator. My husband did the ND Tower and there was a long line to stand in before you finally enter. He said a woman (early 30's) had a serious anxiety attack near the top. You could let your wife do the climb and spend time in ND and the underground museum. Have not done this but the Montparnasse Tower has an elevator (a fee) which would allow some great views. Don't cancel your trip!

I've not done the Arc, but did do the stairs of ND. They are a definite challenge to the knees and there are places up top where you don't have much choice to walk right along the railing at the edge. That said, there is a wire fence the covers up even up on top, so you won't fall over the side, but the stairs are rather intense. (200+ ancient stone winding stairs up, and the same down, and that's if you skip going all the way to the top of the tower.) About 3/4 of the way up there is a small waiting room that I believe connects to the stairs going down, but if it were me, I'd go walk around the nice garden in back of the cathedral while your bride went up and took pictures. It is often a very long line and wait just to get up. You could stand in line with her and then peel off to do your thing while she goes up. That's what my wife did who is afraid of heights. The view is pretty cool. As are the chimera (like gargoyles, but not rainspouts) But as you can see from the photos, you're pretty high up. Ultimately you'll have to decide when you get there. Good luck!

I remember the Notre Dame stairs as very old, worn, uneven, befitting their great age. Great view on top but I agree with the others who suggest you stay below cafe or garden or whatever and let the bride do the climb on her own. My wife and I used that strategy with the roles reversed. Of course your wife will go on and on afterward about the closeup view of the gargoyles and gothic tracery, but you can just smile and nod (as my wife did) and buy a postcard or three or ten. Haven't been up the Arc but it sounds like there's an elevator. I agree with the suggestion of Tour Montparnasse, could be a simpler native to the Eiffel Tower for an elevator-accessed birdseye view of the city. It's also more vertigo-friendly (is that a word?) because you're behind nice thick glass the whole time. And, best of all, you can see the Eiffel Tower and don't have to look at the Tour Montparnasse!
Have a good trip, take it slow, and enjoy the world's most beautiful city.

Very useful advice--and much appreciated!

I am surprised no one mentioned Montparnasse Tower. Read about it in R.S.Paris tour book. Have not been, but there is an elevator going to the 56th floor where the restaurant is, then climb the stairs to the 59th (top). It looks out towards the Eiffel Tower. Costs 11 euros. Sunsets are great, but not recommended after dark. This may be easier than the stairs at Notre Dame or Arc de Triomphe. The time we went, the lines were horrific at Notre Dame. If you are climbing stairs just for a photo shot, there are excellent choices all over Paris, so don't worry about it.
Jana

Lindley I hope you have a book or at least a good blog where your writing gets out to the world . . .your sense of humor and way with a phrase are inimitable!!

Another viewpoint without climbing stairs is the Grande Arche at La Defense (beware the glass lift if you're scared of heights, though). Montparnasse Tower, to quote an old joke told about unpopular tall buildings all over the world, has the best view of Paris because you can't see the Montparnasse Tower.