Hi! My husband and I are going to Paris the first week of September. I've been looking into booking an apartment on Airbnb and was wondering which arrondissement would be best for us. We have friends who have been to Paris a few times who like to stay in Belleville which seems kind of removed to me (at least for our first trip to Paris). I've heard that the metro is wonderful but I'm not sure we want to be on the metro all the time to go anywhere. We live in Philadelphia so we don't mind walking. Also, we are in our early 40's and enjoy going to low key bars and restaurants. I was thinking about staying in the 6th (St Germain des Pres) close to Luxembourg Garden. I wanted some input from people who have stayed in this area. Is it full of annoying tourists? Is it worthwhile to be within walking distance to a lot of the major sights for our first visit? I appreciate your help.

If you want low key bars and restaurants, then stay where your friends do in Belleville. If you want to be within walking distance of the major sights (and major tourists) then stay around St Germain des Prés.
We stayed for a week in an Airbnb in Rue du Cherche Midi not far from the Saint Sulpice Metro Station in Saint Germain.
We thought it was close to perfect, and wouldn't have wished to be any further out in the "burbs". We walked everywhere. Plenty of places to drink or dine, although we self catered most of the time. Pretty busy on the streets ... mostly locals.

As mentioned, Saint Germain would be perfect : you'll find a lot of tourists in Saint Michel which is just next to it. Plus, it's very picturesque! Try the 11th also, which is slightly farther away but full of small low-key bars
BTW we were the last to stay in that St Germain particular apartment ... the city or the building management had shut down short term letting and subletting ... not sure about the status of Airbnb in Paris generally.

That's exactly where I was looking. Glad to hear you had a good time. Did you think that the area where you stayed was less touristy than the northern part of the Left Bank?

BTW we were the last to stay in that St Germain particular apartment ... the city or the building management had shut down short term letting and subletting ... not sure about the status of Airbnb in Paris generally.
I used to rent out an apartment on Airbnb and I've never had a problem (I stopped a couple of months ago). Probably it was because of something wrong with that particular apartment