Campsite in France

Try here

Also might be worth reading this thread as its your first trip

There are a hugh variety of french campsites, along with hugh price differences.
To find the better value one, pick a French town on Google maps, then using the local search function, select camping.
This will throw up the large commercial operations firstly but as you scroll the results, the municipal or smaller rural site pop up, some of which could be a cheap as €25 per night.
For a site with a pool, expect prices to start in the mid €30 for a family.
Local public pools in smaller towns sell a family ticket for as little as €12 for a 3 hour session.
We have often used these in the afternoon and hopped onto an aire or small campsite for the afternoon.

"Local public pools in smaller towns sell a family ticket for as little as €12 for a 3 hour session. "
And that's often where the Aire is situated,beside the local village / town facilities.