Stating at Alex's place had both its good and bad bits. For the price, you have a great location, really easy to get everywhere else in Paris although I'm not sure how safe the neighbourhood is. Alex was really helpful and messaged back immediately leading up to the trip and on the trip. He was also really helpful with advice and it was the weekend of the riots so he told us all about that and why it was going on.
We didn't read all the reviews properly before but we didn't realise he smoked in the house. We don't mind the smell of smoke that much but it did get a bit intense at times. Also the other reviews are correct in saying that you don't feel like you get much privacy. Because alex is in the next room and we can hear him and his friends talking, they can probably hear us. We didn't think this would be that bad but actually when you feel like you have no privacy for the whole romantic weekend away it does get a bit annoying. But we should have read the reviews and found that out before we went.
Also there were many rules we had to stick to that you wouldn't normally have to when on holiday..such as only having really short showers and turning it off when you put soap on, and not eating in the room (we would have not left any mess! But we just wanted to eat in private). This made it feel less like a holiday and like we were tiptoeing around somewhere we weren't that welcome.
But all in all Alex is really nice and helpful and made the whole process very easy for us!