This is a beautiful and charming hotel on a VERY quiet street in St Germain neighborhood. Location wise, I found the very close restaurants quite lacking but couldn’t ask for a more peaceful location. It’s situated in between a bunch of art galleries. I heard nothing from the street at all, and of course it was easy to just walk a little further to restaurants. It is quite a trek to the nearest Metro. 
Staff is incredible, very accommodating and pleasant. One thing to note is that you will leave your key with staff at the front desk whenever you leave. Odd, but as the key comes with a large heavy keychain, I found this surprisingly convenient. There is always someone near the front desk so I never waited more than a minute or two to collect it. 
The room itself was small by American standards but probably average by Parisian, and very comfortable. Bed and linens were excellent. I slept very well here. Room had free snacks that were replenished daily. Note there is a small minibar fridge but it’s barely big enough for drink and honestly wasn’t very cold. I like to buy a little yogurt and cream for my coffee when I travel but couldn’t here, which I found quite frustrating. The bathroom was decent sized and very clean, although the knee clearance when sitting on the toilet was very tight. 
Air con worked great. 
Over all a very comfortable stay and would recommend, particularly for anyone whose highest priority is quiet while still central in Paris.