We had a lovely stay at Julie's flat. It's a little away from central Biarritz but is easily walkable - it takes around 15 minutes to get to the central market. There may be public transport options however we always walked it. The flat is easy to get to from the airport - there is a bus which takes around 10-15 minutes and stops within 5 minutes walk of the flat itself.
We were greeted by a lady called Veronique (we didn't actually meet Julie however she always responded to text messages etc). Veronique was extremely welcoming, she sat me down for about 20 minutes and talked me through everything I needed to know about Biarritz - the bars, restaurants, the beaches how to get to San Sebastien, St Jean de Luz etc etc. An absolute mine of information. She gave me her number and said I could call any time if I had questions.
The flat itself is lovely. It consists of 3 rooms - a decent sized bedroom with a good amount of storage space, a combined living room/kitchen area. The kitchen area is quite small but well equipped and modern with brand new oven and hob. It was great for some self catering - we bought fresh local produce from the market and made meals at home. Then there's the bathroom which is huge. It hasn't got a bath but you could shower and entire family at once - the shower is capacious to say the least. The whole flat is very clean and seemed to have been recently refurbished
The flat had a few basic supplies in stock which was great. This included oil, sat and pepper and a Senseo coffee machine with coffee. When we arrived there were a couple of locally made cakes waiting for us - a really nice touch!
There is a supermarket just across the road which has bread and everything else you might need and the central fresh produce market is not far awaym which has seafood, meat and all sorts of other delicious stuff.
All in all we had a wonderful stay and wouldn't hesitate returning. The only negative perhaps is that the flat is next to a main road which has a some traffic along it during the day, however is mostly quiet at night (although we stayed during some kind of motorbike festival so we had quite a few loud Harley type bikes passing by overnight!). Also the main entrance to the building does not have a lock so is accessible to anyone, although the area is generally quiet and residential and doesn't seem at all dangerous.
Our departing flight was at 5pm and check out is generally at around 10am I think. However I messaged Julie and she allowed us to keep the flat til 2pm which was great. there is also a place to leave your luggage within the building somewhere.
I would recommend a stay at Julie's place - perfect for a couple.