The tricky part, I'm finding, is the change in the spelling of the last name when they then move from French speaking Quebec to the English speaking US. It becomes a "phonetic" spelling which makes it very hard to find death records. My Great Grandmother's name was Marie Celina Dauphinais according to her (French) birth record. Her Father's name was Godfroid Dauphinais and her Mother was Hermoine Rivard. Those names, on the tombstone inscription in Cannon Falls, Minnesota, now read Lena Duffina (Carpentier-married name), Godfrey Duffina and Ermie (Rivour) Duffina respectively. Lucky for me I found the cemetary in which they were buried and will be heading there to find the Duffina family (although I prefer the Dauphinais spelling). I will post pictures if I'm successful in finding the grave markers (I believe Lena's husband, my Great Grandfather, Hercules Carpentier is also buried there) but it sounds like there was some moving of buriel sites so I may not have any luck.
(Old Quebec City pictures nabbed from this website: http://www.tripadvisor.com/LocationPhotos-g155033-w3-Quebec_City_Quebec.html#1604479)
I keep teasing my sister that if I go back far enough in France we may find that we are related to King Louis or one of the King Henry's? Wouldn't that be something...better polish my crown!