[eafkuor]

Depends where you are. In an expensive restaurant (serving real truffles) this is a completely reasonable request

[mdp2021]

You'll be pleased to know that if you went to the places where they do have the truffles in the ground, you do not need the restaurant to be «expensive» to be served real truffles. Black truffles are sliced on your "normal" ~10€ dishes.