We stayed in Jon and Camille’s apartment for almost 4 weeks during summer. The apartment was very nice and location was very good. We spent about 10-15 minutes to the centre and the beach, which was fine. The street also seemed very safe.
Since we stayed during summer it was some days (and nights) very warm due to the lack of AC, and the apartment is located in the top floor.
Camille was super friendly and helped us with our requests, and responded quickly.
All in all, Biarritz is a beautiful city and I recommend this apartment for a stay there :-)