Before the author responds, I'll add that the story emphasizes the fact that the village is in Provençal, south of France, they speak Occitan, not French. That's why their names sound unusual for us (Duomenico, Ninoun, Mamet), and why Duomenico has to translate. For example, the character Guihèn would be named Guillaume in French (guessing both sound roughly like "Gii-YOM"), and Rogièr is the Occitan counterpart for the French Roger (ro-ZHEE).
Also very mild spoilers below:
So, the Historian/Devil just pointedly uses the French — metropolitan, "civilized" — version of the character's name: Dominique. (And btw that name is unisex).
That is also why villagers feel remote from the Crown and alienated from the people in the capital (and also why they are considered / consider themselves heretics, they're leftover Huguenots as the epilogue hints). Hence also the connection with Greeks (Phocaean Nymphs: Phocaea established a powerful colony in South France called Massalia, modern Marseille), and the Farandola they're dancing (the signature holiday dance in Provençal).