I stayed two nights at this hotel which was selected by the conference organisers and cost was 90 euro per night B&B.
I must say that this is a hotel that would sit comfortably in less fortunate cities of the world, but certainly not in the capital of Europe, or in front of Brussels's Sheraton. I hope this review is read by the owners of the hotel who it seems are not bothered by the wear and tear of this hotel, which I think is quite embarrassing.
A few pros:
Great location, a few minutes from Gare du Nord.
Staff were very helpful and suggested a change of room when I complained about how cold the room was.
Free WiFi in the lobby (only).
Breakfast is OK, 2 types of cereals, 2 types of juices, some bread/pastries and croissant, some cooked food, tea/coffee.
A basic minibar.
A TV (not flat screen) with a reasonable selection of channels.
Cons:
Very cold in winter... central heating does not seem to make a noticeable difference. Broken thermostat.
Poor quality sleep comfort (hard pillows, no quilts instead you need to use the bedspread and/or blanket).
Poor décor and e.g. curtains that are basically disintegrating.
No safe deposit box.

Having read the reviews here a day before I arrived, I asked for a room not facing the street, which was quiet.

I stayed here this week for a business trip for one night. First complaint would be that there is no WiFi in the rooms (even paying), so it makes working a bit tough unless you are willing to sit in the lobby and take advantage of the free Wifi. Like other reviewers mentioned, the hotel is clean as are the rooms, but everything looks like it's from 1973. My bathroom looked like a hospital bathroom or something from a mental ward, but it was clean. Terrible hairdryer (also a throwback to the 70s) and tiny, old towels. Staff was nice and welcoming, breakfast subpar but it was included in the very affordable price. LeDome is OK for just a night but I wouldn't stay much longer, though the location is quite good. If you're a light sleeper this might not be the place for you, as starting at 6 am there was a ton of traffic noise.

Stayed in Le Dome for one night during a business trip. First impression reception staff no very welcoming or friendly. Room very dated everything needs replacing. Towels thin and very worn. Didn't eat in the restaruant as no one else was eating there the place was empty. Breakfast basic but edible. Won't rush to go back there, much prefer the Crowne Plaza over the road, but then you get what you pay for at the end of the d

This hotel is clean but lacks atmoshere. I found the green paintwork dull and depressing. Rooms are basis and the double glazing does not cut out street noise if you have a room on the street side. There was an airconditioning unit as an add on but it was so noisy that it was impossible to run while trying to sleep! On the day we stayed there was no hot water in the morning due to a boiler fault. Breakfast was very basic. Not a hotel I'd rush to gop back to!