The actress's name is Margot Stilley. She is most famous for her roles in 9 Songs and How to Lose Friends & Alienate People. Also, she plays Cynthia Plastercaster in the upcoming Hippie Hippie Shake. (Which is a great name for a movie, btw.)
The song is "Mood for l'Amour" by Claire Denamur. An English translation can be heard here.
The dress is Ellie Saab.
The hot bellhop is also the guy in THIS Gillette commercial.
Yes, her eyes are blue at the 10 second mark and brown at the 24 second mark.
And I truly believe in my heart of hearts that the wave in her hair is CGI'ed. Nobody has hair that cartoony. And the fact that they were screwing around with her eye color proves that they had the CGI equipment up and running when they made it. And yes, it's always a conspiracy theory with me. But this time I'm serious. The hair is fake.