We enjoyed our stay in Iswari's apartment! It has a great location and is very charming. This is only about a ten minute walk to the Sacre Coeur and also only about five minutes from Moulin Rouge. Also, within a matter of 1-2 minutes you can walk to some really great restaurants and bars. One other thing to note about the location is that you will have to walk up a pretty steep hill. For us, it was not an issue, but maybe some people might not be able to do that.
She was really quick to respond and good to work with, but one last thing I have to mention is that you should be aware of the rules for the check in. She has included in the description that check in is only from 12-5 and this is because she has her cleaning lady hand you the key. This posed a bit of an issue for us because our train was delayed. We didn't get to Paris until about 6 and were able to make arrangements with Ishwari prior to arriving. It didn't seem to be an ideal situation for her though. We also had to go to the airport earlier than expected the day of check out due to an emergency. So I also hope that wasn't an issue.
Overall, it's a nice place to stay and I would recommend it if your travel plans are within her check in and check out policy and not likely to change.