Unless there was a revolution occurred which I missed in the last few years ( which is possible, I do not follow the "Journal oficiel" anymore) Controllers in France were part of the Public service, cat. "A" ( Ingenieurs) and to be a Cat. "A" French civil servant you have to have the French nationality. Some people recently put France to court arguing that according EU laws ( which superseed national law) all EU nationalities should now be equal. So everyone could apply to any post in theory. Don't know if that court case has ended.
As to the Yank, Tunisians Algerians working, I was told those (about o,1% or 0,2% of the total ?) are all bi-nationals.
But again this might be no longer correct.