We stayed at Clément's place for a weekend and it was absolutely fantastic!
The flat is really homely and perfectly located; it's a 15 minute walk to Sacré-Cœur and ten minutes' walk to the 4 Metro line, so it's super easy to get around and explore Paris. The neighbourhood is great too - there's lots of really good bistros and boulangeries nearby, as well as supermarkets.
Although we didn't get to meet, Clément was a perfect host and made sure that everything was in order. I can't recommend his place enough!