I stayed at the Alize Grenelle for a week, while at a conference in Paris. I originally selected it because it was close to the venue, and reviews here seemed reasonable. It's not a bad hotel. I have fairly high standards about hotel rooms, and this, while far from perfect, was okay.
The room was small, but that's typical for Europe. The bed literally took up most of the room, but really, when you're in Paris, you're in the room to sleep only. The room was not perfectly clean, but not super-dirty either. The walls were paper-thin though. I had a cough, and my colleagues could hear me through the walls.
The price was excellent, especially if you booked online. An identical hotel elsewhere in the city cost us 50 EUR/night more last year.
The breakfast was expensive and not too big. There are bakeries down the street; go get a croissant and a coffee instead for about a quarter of the price.
The elevator was super-tiny, but it was good enough to bring me up to the room with my luggage. The hotel isn't very high, so I actually enjoyed taking the stairs every day.
To save money, the hotel turns off the Air Conditioner every morning. Not a bad plan, but they don't warn you of this. Remember to tell the receptionist to turn on your AC when you return in the evening.
The only real complaint I had was customer service. It has been my experience in Paris that customer service is not a high priority. A group of us had the hotel arrange a trip for us to a show downtown, and the night-shift manager apprently gave us an old voucher with old prices on it. The morning-shift manager had no desire to answer some questions we had, clearly preferring to drink coffee and chat with the restaurant manager, and blamed us for any confusion, since we didn't read the voucher the hotel gave us! She also gave a lot of grief when trying to book taxis and shuttles to the airport.
All in all, the hotel room was fine, albeit small, and the location was excellent. It's decently clean, and as long as you don't mind bad customer service, it's a decent place to stay.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC