The Motion Picture Association of America rejected the poster of the actress, clad only a white dressing gown, that reveals her full silhouette beneath.
The MPAA denied the movie poster of character Ava Lord due to nudity, saying the "curve of under breast and dark nipple/areola circle visible through sheer gown" as grounds for rejection.
Green told Vanity Fair she didn't see what all the fuss was about.
"Oh, my God, I heard about that," she said of the rejection.
"I find it a bit odd. It seems like it's all just publicity -- a lot of noise for nothing. You have so many more violent things in the movie business and this is kind of soft. I'm not naked. It's suggested."
"I find it really sexy, actually," Green said. "It's kind of beautiful. But if it shocks people, I don't know what to do about it. I don't want to upset anybody."
"I don't want to be seen as just the femme fatale or put into some silly box. I hope that people will have enough imagination," she added.
Sin City: A Dame to Kill For opens Aug. 22.