I have been to Paris dozens of times and have stayed at a variety of 5 and 4 star hotels and I can honestly say that this hotel was excellent. It is well situated (just steps from Gallerie Lafayette on Boulevard Hausemann) and a 5 minute walk from the Place Vendome, and the sights of the 1st Arrondisment and quite comfortable with an understated luxury. The hotel has a fantastic history and has hosted ilustrious guests such as Marcel Proust and Josephine Baker (both of whom have floors named and styled after them). It was also the place where the Lumiere Brothers showed the first motion picture ever!
The room was quite spacious and well appointed and the beds, with soft feather mattress toppers, down comforters and 1000 thread count sheets were insanely comfortable and luxurious (which is actually quite hard to find in Europe where even at most 5 star hotels beds tend to be rather hard and spasely appointed). The only real problem with my room was the size of the clothes closet. My closet was less than 2 ft wide and had virtually no room to hang anything. I was there for 3 days and had to keep most of my clothes in my suitcase because I had no place for them. So, if you have a lot of clothes or are coming for a long trip this could be an inconvenience.
The breakfast buffet is the basement, and had most everything one would want, though the service was a bit haphazard (during my stay they routinely ran out of drinking glasses, croissants and other items).
My final piece of advice is NOT to dine in the hotel restaurant, Le Lumiere. We went on our last night because it was a Sunday and many options were closed and the food was overpriced and absolutely horrendous. You'd be better of dining at a McDonalds than dining here. It was truly that bad. But, of course, you are in Paris, so why would you ever dine in a hotel restaurant anyway when you have SO many magnificent options surrounding you.