As the mystical energies emanating from north of Fort Boyard means the region produces more magically touched individuals than usual, Pontroux has grown around the Pontroux School for the Gifted, which formally educates those people in the arts of magic. Research into the origin and technicalities of magic is also ongoing here, though it does appear magic resists the scientific method somewhat.
Pontroux also makes good money selling spellbooks to unsuspecting tourists. They are, of course, completely useless to anyone whose blood is not already fantastically inclined.