Place was a really nice small apartment, great for two people. The location is very good (near the Notre Dame and lots of great restaurants). Too be clear I would totally come back and it's an overall great place to experience Paris.
I'll mention some downsides that did not affect me too much but might be relevant for other future users. Hopefully this is helpful keeping in mind my points above.
The deck was a little too small to use too much and neighbors are right across so there was not a lot of privacy. There was a fair bit of noise from the streets at night (trash collection and people hanging out at night). I was surprised to find out that you pay 50 euro if you check in on Sunday and 50 more if it's after 8pm. We had a delay in our flight and had to pay 100 euro on the spot which was unexpected and unpleasant. Elevator is very small, a big person might be too comfortable.