Indeed, I had even unexpected before that Buttes Chaumont hotel would be so comfortable and cosy. It is located near metro stations, bistrots, shops, markets and you may rapidly reach the center by using 5 and then 1 lines of metro. Note that there is a nice park (with the same name as the hotel) in 10 min by walk along the street. Rooms are well furnished and decorated, very clean and cosy, albeit may seem small. I lived in room 304 and liked it. It was unusually cool in Paris and room heating was OK. A double bed was very confortable to sleep. Three young men that work at the reception and the woman at the kitchen&bar are always kind and friendly. Continental breakfasts (bread, croissant, jam&butter, juice, coffee, tea) were tasty. I strongly reccomend to store your documents and valuables in the safe box at the reception; a copy of ID or passport front page is OK.
A note to travellers who visit Paris for the first time. Be very careful in streets, crowded places, and subway. Pickpockets, thieves, beggars are plenty. An ideal position of your closed bags is on your belly.