October camping in France

Hey all. I'm about to start a cycle tour in France.

I've been checking camp sites on Google maps and it seems that many close at the end of September. Starting in Normandy and on my way to Spain via the Basque Country.

I'm concerned of finding open camp sites in October. Any tips on where to camp, and of it is possible to camp in municipal or other camp sites off season?

Any other tips welcome.

Merci