Fonti is generally sicilian and now it has spread all around Italy and in USA too. A part of the sicilian Fonti comes from the little island of Lipari belonging to EOLIE ISLANDS, North of the sicilian coast. These islands are appreciated by german tourists too. So in Sicily Fonti is considered a "liparota" surname. In spit of its diffusion around Italy, Fonti has undoubtely a local "taste".
I am not sure that it has the sane origin of the french variant "Fonte"