It will be a long time before I work with a composer on the soundtrack for La Seduzione, but when I make a film I find that I start referencing music very early. Usually I'll discover a song that captures the mood of the piece, particularly the feeling at the end of the story -- the feeling I want to leave the audience with. Then I'll play that song over and over again while I match it with the images in my head. When I made my student film at NYU it was Frank Sinatra singing That's Life. With It's About My Brother it was Buddy Holly crooning True Love Ways.
I'm not sure what "The Song" will be for La Seduzione but I've been listening to a lot of stuff from the sixties and seventies: Perez Prado, Tom Jones, Brigitte Bardot, Tijuana Brass, Les Baxter. It's stuff that feels deliciously dated but at the same time is genuinely witty and playful and fun to listen to. I've become particularly fond of some Italian soundtracks from the sixties, especially a composer called Roberto Pregadio. He wrote music for the so-called giallo, the Italian exploitation pics of the era.
Here's one piece of his called Iena Sequence. And this other one's called Eva, La Venere Selvaggia, which I think means "Eva, the noble savage". (Doesn't that make you want to see the movie?)
If you want to hear more of this kind of music I would suggest Beat at Cinecitta, a sampler of soundtracks from Italian movies of the era.