2 weeks in France with reluctant teenagers in tow

We fancy a change from the UK this year, and hopefully warmer weather in France. We dont wish to travel too far south and love being near the coast.

We love smart, very clean sites with good pitches and some facilities (a pool is essential but would rather no entertainment)

We are travelling in peak summer weeks - being married to a teacher has some down sides!! So would welcome any good suggestions.

Our only impression of French sites to date has been very neutral.....nothing like the UK.