I don't think you'll find a better location in Biarritz than Herve's flat, it's so close to the beach. It's also surrounded by a great buzzy area with restaurants and bars, but doesn't feel too noisy.
It's wonderfully furnished with good personal touches - sometimes Airbnb rentals can feel a bit anonymous, like everyone has bought exactly the same things from Ikea, but Herve's apartment felt and looked stylishly different.
Herve is a great host, very attentive and quick to respond to questions. His recommendations for bars and restaurants were spot on.
We had a fabulous time in Biarritz and would highly recommend this place.