Where to spend your holidays in the summer ?

It all depends what you are looking for. My own region (near Ledenon race track and Avignon city) is a good compromise with good food, spectacular sceneries and landscapes, nice and warm weather (a bit too hot in summer for some) and a lot of summer concerts and festivals in all kinds of music, theatre and entertainement. The sea is just one hour drive away, and the mountains, another hour drive in the other way.
Another region I'm fond of is Alsace, with a mix of French and German assets. Very nice architecture, very orderly villages, excellent wines and great welcoming people.
I also love Burgundy, which is lovely calm and relaxing, with best wines and food you can get. Great historical places. A great place to spend holidays when you are really tired by your work.
Last for having fun, going to dance clubs at night, surfing on endless beaches, enjoying great sunny cuisine and meet cheerful people, the south western coast of Basque country is a great place too.