I've stayed at the Mob Hotel in Paris twice - https://www.mobhotel.com/paris_en/
and I love it.
It has a very bohemian, relaxed vibe. The bedrooms are small, but adequate, clean and modern. The beds are super comfy, there are some shadow puppets you can use on the wall, a mobile phone to make free calls and gorgeous shower gel /shampoo in the bathrooms in refillable bottles. The food is local and organic and the breakfast is delicious.
This place is very much for the more sustainably minded guests.
The downstairs dining area and outside space are great for just hanging out and local families (not staying in the hotel) come for dinner and events there too.
It is in a Northern suburb of Paris, L'Ouen where all the furniture flea markets are - well worth a visit if the weather is nice and you fancy a walk. Otherwise, it only takes about 10 minutes on the metro to get to central Paris. The metro is about a 5 minute walk from the hotel.
I'd liken the area to Shoreditch in London - it's a bit further out but very cool and edgy.
I haven't taken my kids yet but I've seen many kids there. Plus the rooms are very decently priced.