For an uncomplicated and oh-so-tasty burger you have to go to Biarritz (where you want to go anyway; it's my latest crush!) at Le CAB - Le Comptoir a Burger. There is so much more to say about it that they are also open for lunch, that they are located in a non-touristy and very pleasant street, that it is best to sit outside and that, as mentioned, it is delicious. Le CAB