French culture: when the Sheffileld son opens the door, the French tutor kisses Brighton on the cheeks. Unless immediate family, French men do not kiss each other, merely greet by shaking hands. And, in such a professional relationship, which is brand new, that would be completely inappropriate in France.
The French taught Brighton is wrong: he says "mon chéri" but that is masculine. Meaning he is saying "my darling" to a man. Instead, Brighton should have said "ma chérie", since they were talking about men romancing women, not other men.
The resistance was fought valiantly by the French. In fact, the French have won many wars, and have even saved the Americans' skin in theirs.
As seen in the movie this is based on---Green Card---the green card checking official would not ever come before two people are married. Since no marriage has taken place, no potential fraud has yet been committed, therefore no government official needs to come interview anyone. And they would not come to someone's home, the couple would go to their office.
When he meets Sylvia in the kitchen, the French tutor is dressed like an Italian peasant instead of a snappy dresser Frenchman. He is wearing a loose thistle vest on top of a mandarin collar peasant shirt with bouffant sleeves and sage colored pants. No urban Frenchman would wear such clothes, unless he were working the fields in the countryside.