As young student/professional I am sub renting a nice room with bunk bed in Paris.
The flat is quite big (with a living room) but need to be reformed (bathroom).
It is not very luxurious but it's ok for low budget sop.
It's a quite neighborhood with a lot of supermarkets, the fleet market is really nice to visit and you walk up to the Sacré Coeur.
The subway is at 3 mn walk (Porte de Clignancourt L4). You will be at the center of Paris in 20 mn top.