5th Arroondissement

I have stayed in probably 15 hotels in the 5th arrondissement. You may want to narrow it down a bit with budget or a specific area of the 5th. Below are several at different price points that are good choices. I've stayed in all but the last two though I have visited them and in the case of the Excelsior Latin been in their family room.
https://www.hotelmonge.com/
https://www.hotellesdamesdupantheon.com/
https://www.hoteldesgrandshommes.com/
https://hotelpetitparis.com/en/
https://www.residencehenri4.com/
https://www.excelsior-paris-hotel.com/
https://www.paris-hotel-des-nations-st-germain.com/en/

Henri IV Rive Gauche is our go to when we need a Paris hotel

Hotel des Grande Ecoles is attractive because of its garden but it is un air conditioned and the last time we stayed there our room was near 100F by late afternoon in. early June and didn't cool down comfortably all night although the air outside cooled.. It was also very run down but they may have upgraded since then.

I recently enjoy the Parc Luxembourg, which should be close enough

I have been to Paris several times and have never stayed in the same hotel twice..........I'm still trying to find the one that fits best.

When I stayed in the 5th it was at the Hotel du College de France back in 2011 (can't speak to its quality now). It was a good, clean hotel and I had a pleasant stay there. The room I had was nice enough, a decent size but nothing fancy. I didn't have a view or terrace but I'm pretty sure there are rooms that have one or both available, if that is of interest to you.

We're booked into the Hotel des Grande Ecoles later this spring. We've never stayed there, but many Forum folk recommend it. We usually stay in the 7th, but I thought it was time to try another area. We enjoyed wandering around the 5th the last time we were in Paris, so it seemed a good choice.