Hiding behind a wall masturbating watching a couple fuck. What movie?

[Leroyeur]

Been looking for the movie of this image, or just the scene for a long while. It's my favourite scenario.

http://68.media.tumblr.com/6f99f88467fe36165605aeeedb5395a9/tumblr_oemyq1NFdk1st7pw8o1_400.gif

• 
  Sneakily masturbating girl
  Watching couple Fuck

Bonus if she joins them