Possibly Provence?
So many international companies are now recruiting in sunny Provence that the expat community is growing, as is the range of schools available. There is the choice of state or private schools - French state schools will allow for total immersion, strict French routine and regular testing.
Private Schools
Private schools are unregulated - so choose with care! Most have a mixed international intake, some have mostly French students wanting to learn English, all will have an international curriculum which might be more useful if you are moving regularly. There are also some private schools which are set up with varying degrees of accountability and surveillance by national or international bodies.
The most obvious choice of international school is the International Bilingual School of Provence which offers the alternative of the French curriculum, leading to the French Baccalaureate and Brevet or the British option of IGCSEs and then the IB Diploma.
There are also several elementary schools, one Catholic school with a bilingual section (Ste Catherine de Sienna) and two all-through schools. Sainte Victoire International School in Fuveau offers full and weekly boarding and a French curriculum or IGCSEs followed by the IB Diploma and Val Saint André International School is a day school offering either the French curriculum or IGCSEs and then A-Levels.
State Schools
There are an increasing number of French state secondary schools that have international sections. If you can get into one of these schools, your child will get an almost free education with French children. They will however be immersed in a totally French environment and the education is based on the French national curriculum and so might not be suitable if the student is only attending for a short while, only to return to their home country or international schooling afterwards.
Schools with international sections often chosen by expats include College Jacques Monod, College Mignet, École Internationale de Manosque and Lycée Georges Duby.