We had an excellent stay at Mercure Paris Notre Dame Saint Germain des Prés. The location is perfect—central, walkable, and close to Notre Dame, Saint-Germain, cafés, restaurants, and transportation. The staff was very helpful and welcoming, and the hotel was clean and comfortable.
The room was a little small for two people, but that is expected in central Paris and was not a problem since we mostly used it for sleeping and resting. Overall, a great stay and I would definitely recommend this hotel.