Song in Hotel Nightclub
I loved the song Hubert sang while pretending to be a "traditional" musician. It's called "Bambino." Here's the original version by Dalida, which was a huge hit in France in 1956-57 (thus slightly anachronistic for the film), although not as well known in the US:
http://www.youtube.com/watch?v=6U0NlPgvRuI&feature=related
It's so funny that OSS 117 knew no Arabic at all in one scene but a few scenes later can sing an entire pop song in Arabic. And learned hieroglyphics at a glance!
Probably not so coincidentally, Dalida was born in Egypt (although she was of Italian descent). The scene was clever on so many levels; it's one of my favorites in the movie.