IT'S ALL FRENCH TO ME I

The following phrases are English translations from French. Can you supply the original French phrases - which are often themselves used in conversational English?

1. On the contrary
2. Nanny
3. Very frightening or unwelcome thing
4. Love letter
5. Look for (blame) the woman
6. Required - as in fashion
7. Social gaffe
8. Dark, menacing movie style
9. High fashion
10. Sea sickness

Answers:

1. Au contraire
2. Au pair
3. Bete noir
4. Billet doux
5. Cherchez la femme
6. De rigueur
7. Faux pas
8. Film noir
9. Haute couture
10. Mal de mer