France has thousands of sites, many very popular with Irish and British, teenagers and others alike. Have a look at Keycamp website, Siblu.ie. Siblu has a site at St. Jean de Mont in the Vendee area of France, very popular with teens, but the choice is really huge. Most of the 4 star sites are popular with above, including teens.
A work colleague recommended a place called Camping Barcelona. It's in a place called Mataro which is approx. 20miles from Barcelona. Accordiing to him, his 2 grumpy teens weren't grumpy for the 2 weeks they spent there. If the kids are happy, it does make for a great holiday
I HIGHLY recommend Union Lido near Venice. www.unionlido.com
Huge amount of things to do for teenagers,there's also a fabulous water park nearby and plenty of nightlife.
If you don't to drive there with your own tent you can Ryanair to Venice-Treviso and there are several major companies that offer fixed tents,bungalows etc on site.
My teenage lads thoroughly enjoyed the place.