Kais's place is in a great location in Montmarte, a short walk from a bunch of bistros, a central metro station, and plenty of pharmacies and markets. The unit itself is on the smaller side, but provided plenty of space for our purposes since we weren't going to spend much time there anyway. We didn't do any cooking, but the kitchen was well-stocked with everything we might have needed, and he provided an espresso machine with plenty of pods which was a very nice touch.
A couple minor complaints were mostly centered on the bathroom. For starters, it didn't look like it had been cleaned all that well (e.g. hairs in the shower), and the towels provided were clearly very old and didn't smell great. The shower also has no door or curtain, which I understand is not unusual in Europe, but ultimately there's not way to take a shower without the bathroom floor getting water all over it. On top of that, the hot water would typically run out within 10-15 minutes, so forget taking a shower after someone else.
Ultimately we were satisfied with our stay based on the low cost for the apartment, but had we been paying more these issues would have been unacceptable.