I booked my son a hotel just north of the Luxembourg Gardens, in the Latin Quarter, glad to know it’s a good area. Air BnB’s didn’t look like a great deal in that location, so I just went with a smallish hotel, it looks very nice.
Great ideas all, I’m going to pass these to my son. Thank you all for the help!
We enjoyed staying near Notre Dame for a week in 2018. (Different situation - 2 couples in an apartment). The 7 day museum pass did pay off for us financially, but we found the big advantage was being able to go to the “short line” (they still need to check your bags).
We devoted one day to Versailles, outside of Paris. Would have loved to do the bike rental for seeing the grounds, but due to limitations of the group used the tram - that worked nicely too.
One thing we have really enjoyed are taking tours thru Paris Walks at paris-walks.com I don’t know how many they are currently offering but we’ve enjoyed all the ones we have taken over the years.
@busdriver11 - that location should be great for your S to see all he wants to of Paris!
Highlights for us (our kids were 15 & 17) were Musee d’Orsay, Sainte Chapelle, walking along the Seine, and a day trip to Bayeux to see the tapestry and do a D-Day tour.
That was one of the areas we considered. I bet it will work out great.
I want to second the Fat Tire bike tours. We did the night time one that also included a boat ride on the Seine. And an ice cream stop at Berthillon. Riding my bike in circles at night around the Pyramid plaza of the Louvre is one of my favorite memories.
Fat tire and other bike tours are always a must for us. Ourrecently college grad nieces did it a few weeks ago and they agreed it was a highlight plus unlimited wine was served on the boat cruise 
Loved biking around the Louvre at night - our kids were preteens when we did it and we had it to ourselves along with friends on the tour with us. Great memory !
We’ve lived in Paris and visit often. Google metro and bus pass. You don’t want the tourist one. Get a regular one. It’s called a Navigo pass. Son can get it at the airport in the train station. Or at any train station. Take a passport size pic for the card.
Many, many museums are free for students under 26. Does he have a student ID? No need to get the museum pass.
Latin Quarter is definitely the location I’d have suggested. If I can find my tip sheet, I will PM to you.
Thank you, @MIP750. He will be 28, so too old for the student discount. Thank you for sending that PM, that looks like a fantastic guide!
We did a graffiti tour of Paris and it was fantastic. Our only regret was that we didn’t do it earlier in our trip as after we noticed so much more art around us. Our tour was in the Belleville area which is slightly off the usual tourist destinations but easy to get to via the Metro, so felt like we wee getting a totally different feel for the city. It looks they have more offerings now.
Reading the reviews, it sounds like it’s hard to find the meeting place and it can be pretty disorganized. Did you have any trouble?
It was just down the block from our hotel on Rue De Rivoli - it was sort of in the middle of nowhere. The bus driver was great and made sure we stopped just by the Effiel Tower when it did its special light show (like once an hour).
I did that night lights tour in 2013 with my daughter but also over 30 years ago with my husband!
I can’t believe our two trips to Paris are 34 years apart! I was so young, the same age as my middle kid.