We stayed at the Hotel Gramont Opera for 4 wonderful Parisian nights in April 2013.
First off, as many others have said, the service here cannot be beat. From check in to departure the staff was bright, cheerful, accommodating, and friendly offering a bon jour or bon soir whenever we came or went. And everyone spoke fantastic English, which came to be very helpful.
Aurélie and Anne-Flore ensured that everything was coordinated upon arrival, including our Paris Museum Passes (Which are a must!). Sandra was personal and helpful at the front desk helping us with dinner recommendations and reservations, even asking how the meal was the next time we saw each other. We got assistance from do's and don'ts of the metro and RER to local things to do after hours...they ensured that our stay and trip was wonderful and memorable. The croissants in the lobby are worth a mention as well, makes for a very good welcome/re-welcome to the hotel after a day out...wonderful snacks.
The only discrepancy with our stay (Which is the fault of when we booked, not with the hotel) was that we had to switch rooms on our last night from a Superior Double/Twin, to a regular Double Twin room. Both were very good size for European hotel rooms. The WiFi was fast and fantastic (With a universal code for all your devices, not separate codes that expire every 24hours which seems to be very prolific around Europe). On the day we had to switch, the staff said we could leave our bags in the room and they would move them...and they did. The only incident, since our room was not ready when we moved, was we had a bottle of milk and yoghurt in our minibar fridge that needed to be moved as well. The yoghurt made it, but the milk was inadvertently thrown out. The hotel bought us a new container and placed it in our new room by the time we were in for the night (All without prompting from us).
The room was always clean and comfortable upon return. There was a bit of road noise at night, but nothing that couldn't be ignored after a long day of Parisian trekking. Excellent air conditioning would make for a very comfortable room in the summer, not really needed during a Parisian April. My wife had some issue with the hair dryer in the bathroom (Not enough air output), so for all concerned females, I would suggest bringing your own.
We had the hotel breakfast one morning. I would suggest that there are better options stopping at a local patisserie on the way to wherever you are headed that morning. While it was good (Especially the eggs on request) you are in Paris, go eat local.
The location in the 1er was exceptional! Around the hotel, there is a options a plenty. A Monop (Local grocery/market) within a 2 minute walk (Intersection of Rue du 4 Septembre and Gramont) provides a good stop to pickup water, soda, and snacks (For us it was milk, waffles, and applesauce packets for our toddler) at good local prices, a must before going to the pricey Parisian tourist spots.
Several Close Metro stations make getting to popular tourist locations a breeze. Your first stop should be the Opera Metro station to pickup a carnet of 10 billets (Metro tickets). The Opera station is a great hub, and a straight 3-5 minute walk down the Rue du 4 Septembre or from Bd des Italians from the hotel, passing many cafes, patisseries, brasseries, and a few creperies (Or lots of trattorias on Bd des Italians) on the way. Speaking of creperies...there is one we frequented about midway between Gramont and the Opera metro, serving savory and sweet alike (Along with paninis and cold sandwiches), and was a good quick bite to eat on the way back to the hotel with a tired toddler, or a good late night snack.
Finally, the placement of Gramont makes for a lovely morning walk down to the Louvre, Jardin Tuileries, the Champs-Élysées, and the Centre National d'Art et de Culture George Pompidou.
Have no fear about staying at the Hotel Gramont Opera, especially with kids. We had a wonderful time and would rebook in an instant. Special thanks to Sandra for all the help with dining bookings!