We're being a bit conservative here. The MPAA might settle for a G.
Why'd we bump it up? Because even though the sexiest things that happen are Elisa's almost touching the tinker's trouser leg and staring at herself in a mirror, there's a sexual undertone throughout the story that can't be denied.
Elisa is a grown woman, after all, and she seems less than fulfilled by her husband. But just what exactly she wants from the tinker is left up to our imaginations.