I once saw a western, I can't remember the name of the movie, about a fort in far western Texas, circa 1863, where a small contingent of French soldiers crossed the border and came to this fort in CSA territory that was under siege from Indians [Apaches or Comanches, I can't remember which] and the two groups fought together against the Indians. The CSA commander was an asshole and the French officer took temporary command of the fort with the approval of the leading CSA noncom. So it was like 'as one white man to another, we have to hang together to fight the red savage' and of course, they won, then at the end, the French re-crossed the Rio Grande.