I am not aware of that (the contracts).
I don't think they did it for any moral reason at all. I think they did it because they believe (this sounds better in a French accent, à la Monty Python/Holy Grail)
that the imperialist American Gouvernnement wants to take over the world, and forever damage the French way of life.
And I can't entirely blame them for thinking that. The French have always been worried about it (presumably since Hitler) and if they aren't pissing off the US they are
pissing off the English.