We were looking for a mid-priced, comfortable hotel in a good location, and the Hotel de Sevres filled the bill. Situated near the St. Placide Metro stop, it allowed us to get to the Gare du Nord, the banks of the Seine, the Louvre and Notre Dame or to Montmartre in no time. The breakfasts were good and the staff were friendly. The lcoal streets were worth time spent wandering in them. A block and a half away is Le Nemrod restaurant, which is not gourmet class but is good and reliable with plenty of French atmosphere.
Good breakfast buffet for less than the cost of a croissant and coffee at nearby cafes
The windows open!
Small room, small bathroom - but you're in central Paris and not paying a fortune, so it's appropriate.
The mattress was quite firm - firmer than I like.
If you want a large room with lots of amenities, go elsewhere. But if you just want a comfortable, friendly base for exploring Paris, I recommend this hotel.