We stayed at Caroline's place as two moms with our sons (aged 11 and 12). The location is excellent - just a short walk to the beach and downtown. The space is also stunning, with a roof terrace with excellent views of the ocean. Everything was very clean and orderly when we arrived. Claude who works with Caroline met us promptly and was extremely helpful. The apartment has three bedrooms - the loft upstairs is perfect for children (not really for taller people as it has low ceilings with lots of beams criss-crossing). The kitchen was well outfitted and we had several meals at home which was relaxing.
The apartment is at the top of a large house - and so there is a considerable walk up stairs - which we enjoyed, but might not be for everyone.
Biarritz had tons to offer our active kids, and plenty of nice places for us to enjoy a great meal and bottle of wine.
Overall, the trip was excellent and the apartment was really fantastic.