Sie san a heu bei der Franzos.

13:03 Sep 29, 2017 

Being from Northern Germany I am reading it as "Sie sind ab heute bei den Franzosen" or "From today on, you are French" as in he is declaring him a Frenchman because he does not like people from other regions, but I think the suggestion below also has a lot of merit :-D

10:45 Sep 29, 2017 

so don't rely on my opinion, wait for more comments.
I don't think "heu" means "hay", it is probably short for "heuer" which means "this year".
the "a" just before "heu" is probably short for "auch".
My interpretation of the whole: This year (nowadays?) you (the region where you live) are part of France/the French people.
Incidentally: the Saarland (I lived there from Dec. 1959 to Jan. 1978) was and is German/German speaking, only a small minority wished to remain part of France (it was under French control from 1945 - 1956) in the plebiscite.