You can find French genealogical word lists, and with that and some information on the format of French parish records you can usually get by.
If they arrived in late 1600s early 1700s, and they were Protestants, then they are most likely Huguenots. The Edict of Nantes was revoked in 1685 and post that date huge numbers of Huguenots emigrated.
http://www.huguenotsociety.org.uk/ is a good place to start. Try just searching on Huguenot and the surname of the family, or Huguenot + the town in Staffordshire they lived in. To get back to France you will need to work out where the family came from, but there is quite a lot of Huguenot information online and you may find that your family lines have already been researched.