That's one, though it's not very "fresh" for kids that age, as usually they've been read it, explored it in class or saw the play before that age.

Among the classics, Daudet is also read at a young age. And Jules Vernes. Dumas but a few years later (nowadays). All of them less so then it used to be. It's more around 14-16 we're introduced to the classics in school.

None of these books were written for kids, though. There's no strong tradition of literature for children going way back as exists in the UK.

But there are literally tons of contemporary books written for 11-12 y.o., even more so in Québec (where these generations of authors were more influenced in their childhood by british youth literature, both in translation and in the original, in books or through TV/movies. French Europe is picking up pace, but is still behind. Even a series as famous as Narnia didn't get translated before the movies, and so far with little success). Some rival the local sales for kids of HP, Fowl etc. (Amos Daragon, Amélie Laflamme, Mademoiselle C., Les Chevaliers d'Émeraude etc.) and have fair success in France too. Two of those have their very sucessful movie series, a third is in the works. They come in a variety of genres, from realism (educational or not) to magical realism, mystery, adventure and anglo-saxon style Fantasy. The most thriving local publishing houses are those for children.

We don't know these books much because a) we were not raised with them and b) they don't have an adult readership (nor movie audience), in the vein of HP's. It's not because of the books - those I had to read (because I was on the design team for the movies, or because it was written by my cousin) were no more no less mature or interesting for adults than their English counterparts.