My husband and I stayed in this apartment for three nights and it was quite small once all our bags were in and we settled in. I wouldn't put any more then two people in this apartment. It was well positioned as it was close to the main attractions via public transport or walking (30mins walk to Eiffel Tower, Notre-Dame etc). There was a taxi depo 5 minutes away, train and bus close by too, lots of restaurants around, small shops and a local supermarket about 5minutes away as well.
There is a lot of cracked paint on the walls, the bath room was the same cracked paint & mould behind the toilet that looked like it was leaking slightly, once we had a shower it felt damp in there for the rest of the stay as it was not well ventilated.
It states there is air conditioning but it's just a small thin unit you plug in and only just makes the air bearable, I would not want to stay here in the middle of summer with only that to keep us cool! You are on the ground floor so you tend to get a lot of the street noise. It didn't bother us to much but it could bother some as the apartment is in a busy area of the city.
The owner was very nice and understanding after our flight was delayed causing us to arrive late and my phone wasn't sending messages correctly. She waited for us till we arrived and then showed us the apartment. I did send some messages over Tripadvisor but she didn't see them or didn't respond. I did send some messages throughout our stay but had no response. The owner was flexible with our checkout time which was very nice.
I do think the apartment is over priced considering the size and condition. It's probably only priced that high due to it's location.
I would recommend this apartment for short stays, for no more then two people and if you are prepared to deal with the above.