Paris hotel for family

Two hotels....

In the 7th Hotel Muguet....

Or in the 5th Hotel des Grandes Ecoles.

I think you will be happy with either

www.paris.fr

I stayed at Ibis Paris Gare du Nord Chateau Landon which you can find at www.accorhotels.com

It's a 5 minute walk to Gare du Nord train station and connections to many Paris Metro lines - also, Gare de l'Est is a 3 minute walk and the Louis Blanc Metro stop is a 1 minute walk from the hotel.

Considering most Paris hotel rooms are very small (especially if you don't want to spend a lot of $$), Chateau Landon had a good amount of space (even the bathroom). Also, it's got air conditioning and an elevator - great for July when it can be hot and you are tired or carrying a lot of bags.

They do serve breakfast, but it costs extra and I never bothered since there are a lot of restaurants and cafes nearby. Chateau Landon doesn't have on-site laundry facilities, but there is a self-service laundromat 1 block away that's open late.

Tip: ask for a room on the 7th floor (top floor) - I had a nice view of Sacre Couer cathedral and the hills of Montmartre from my room.

The Hotel Valadon in Paris has been recommended to me to a stay we are planning in June

The area around Gare Du Nord is not too thrilling, I wouldn't aim my search around that area unless you are literally spending on the night and leaving in am on train.
Do start some seriuos looking now for a room. Quad rooms are hard to come by, many hotels only offer 1 or 2 such rooms and they book fast( especially the insexpenisive but well recommended ones)
Have you looked at tripadvisor.com , the paris forums there are great , and there are hotel reviews that are posted by readers and are most helpful.

It is not hard to get to the Eurostar from the City. You might want to look at an apartment if you are staying in Paris for at least 3 days.

For the same price as a hotel, you can all stay in 1 apartment, have a kitchen and in some case, a washer/dryer.