"Ancestors & Descendants of Joseph Shomo (Shammo) Immigrant to Pennsylvania 1750", Peggy Shomo Joyner, 1983
This book is available at many large genealogy libraries. Unfortunately, this well-written book is out of print and this is one of Ms. Joyner's books that has not been microfilmed by the LDS church (at the request of the author).
Joseph Shomo/Chaumontet, the immigrant, came from the duchy of Savoy. In the mid 1700s, this area was NOT part of France, but it is today. See (enter this url on one line):