Winter stopovers in France

I am looking to travel through France to the south of France and then on into Spain. Starting in September from Calais and returning in December. I have planned my route and want to make to two night stopovers on the way through France. The problem I am finding is that traveling down there are plenty of sites open but coming back I can't find any sites open. Can anyone advise me of  sites I could use travlling through France and at Calais which are open all year.