Mathieu's flat is lovely and a great place to stay at while visiting Paris.
The flat is very well located in the 2nd Arrondissement. It is very close to Rue Montorgueil which is a street with cozy bistros, boutiques, and bars. I really liked the area to escape the tourist flooded city center.
The flat is on the second floor and the neighborhood seemed safe as well. There are two metro stations a few minutes from the flat which are well connected to the tourist attractions.

The flat itself was very nice and very clean. And if you pay attention you will see that it has been decorated with a lot of care and attention to detail. I cannot say that the flat is very big but I still felt extremely well and comfortable. And as you probably will be mainly using the apartment for sleeping, it is worth to mention that the couch in the living room folds out to a huge double bed. Of course there is also a double bed in the bedroom.

Mathieu seemed extremely nice over emails and text and always got back to me very quickly. I felt like he really cared about making our stay as nice as possible. I unfortunately didn't have the chance to meet him personally but hope to in the future. I would definitely recommend this flat to anyone who is looking to explore Paris and would like stay in a modernly decorated flat with the nicest host possible :)