First of all, keep in mind that all Paris hotels are more or less overpriced. In that sense Mercure Gobelins is a fair deal, good value for money. (I paid 130 EUR for a night). It has all the necessary amenities for a 4*, looks very new and nice from the outside, has a reasonable location. Nevertheless, there a few points to mention.

1) Rooms.
Very small, which is common for Paris and London. I can't imagine how do people stay in 2-3* hotels! This one had a nice, although simple, decor, comfortable beds with a few pillows, clean bathroom with a bathtub. All the rooms with a bathtub have a kingsize bed, while those with a shower - two twin beds. Don't know, why. :)
Look for a room on 4-5 floors - there are only 3-4 rooms on these floors. Less neighbours - less noice.
Important: if you stay in Winter (like i did) - ask the receptionist to turn on the AC (which works as a heater). Otherwise the room would be extremely cold.
2) Location
Nice quiet area. Hotel is just round the corner of Place D'Italie Square, which has a few restaurants (mostly italian), McDonalds and KFC, and two subway stops (both named Place D'Italie but of different subway lines). By subway you can reach the city center in 10 minutes (as well as Gare Du Nord station - if you travel by train to Koln or Amsterdam). Instead we used to walk - it took us 10 minutes to get to the Seine, 20-25 minutes to Notre-Dame. Road to center passes through the Latin Quartier - beautiful and colorful area, full of shops and cafes. Highly recommended in early spring or late autumn!
3) Breakfast.
Reasonable if you get it included in price. Otherwise do not buy it - it does not worth 15 EUR they're asking for. Juices are awful, so is coffee and tea. Liked only pastry and fruit salad.
4) Service.
Staff hardly speaks English (also a common thing for France), but somehow we understood each other. Everybody's smiling and wishing you a nice evening, it made us feel welcome.

I stayed two days at the Mercure Paris Gobelins, booking through the Mercure website. The location is really good, close to the metro line. There are some cafes near the hotel, as well as a shopping mall with around 40-50 shops and a supermarket. A taxi ride to the Bastille at night is not expensive (to enjoy bars and the nightlife), as the hotel is also close to the region. The hotel room is well decorated, clean and spacious. The room had a lcd TV, great shower etc. The staff is also attentive and polite. I would definetly go back to staying at the hotel, as it was great value for money - considering most hotels in Paris are a rip off!!

As finding a good and central hotel in Paris is not easy, a friend of mine recommanded me this hotel, in the very heart of the 14th arrondissement of Paris. It's very near the nearet metro station and very handy to get around Paris. Since I used to work in the hotel business, I am quite demanding with hotels. They were able to give me a very nice room, that was very bright, on a high floor, so that it was very quiet. The bed was very good and firm and the bathroom large enough with a nice bath, and well equipped. The Buffet Breakfast is very nice and has lots of different breads, juices, etc... Since I had to catch a train to Biarritz very early in the morning, I couldn't have my breakfast, and couldn't get any b-fast package ( a sort of small breakfast package).. Dommage ! The reception staff was very helpful with reserving taxi, providing information regarding paris, maps,etc.
I would definitely return to Mercure Place d'Italie.

Good hotel for small vacation or week-end. Located near Place d'Italie which is a bit far from center, but this is reflected in the price. However, you are not lost with only 2mn from underground with many lines available. Room are small but completely new and modern, especially the bathroom. Neither fridge nor water boiler in the room, but with safe. TV is old but with main channels. The mattress is excellent, not too hard not too soft. The breakfast is served in a nice decorated modern room, with a giant buffet with almost all you can expect from a breakfast. It has a terrasse to eat outside in summer with tables and seats in wood. Staff is nice and helpful, except one man at the reception who is arrogant and unpolite.

We were in one of the two rooms on the ground floor. I do not recommend them as just near the entry and a bit noisy, in particular at 05:00 when the employees push the laundry wagon on pavings. A further negative point, the windows behind the big curtains where neither closed nor locked when we got the room, what we only saw the next day.

To conclude, it is a nice, small and modern hotel for travelers looking for a place to sleep a few nights. Price is reasonable, this is due to the fact you are not in the center and have small room not with full equipment.