As others have said, this is a quirky flat, close to the Métro, easily accessible from Gare du Nord, and close to amenities. Clean and cosy too, with constant hot water and wonderfully warm (we were there in mid-January).
Some guests might have a slight issue with the location of the shower and toilet; it didn’t bother us much - we are good close friends who can cope well in unusual situations, and find the funny side of things. But if you are travelling with someone for whom personal privacy is very important, this apartment might not suit you. That said, the shower is wonderfully spacious, which is unusual for a small Paris pad / hotel room. And the kitchen, while small, is well equipped for simple meals in. The sofa bed (which I slept on) is surprisingly comfortable, too.
So while it has its quirks, this is definitely one for very close friends or couples, perhaps including a young child. I highly recommend this one if you can cope with a few little oddities - I’d certainly stay there again, and my friend said she would too, so we are two very happy guests!