A Peephole(2013)

Original title: ノ・ゾ・キ・ア・ナ

Kido Tatsuhiko moved to Tokyo to attend an art school and start his new life. In his new room, there's a small hole in the wall. At first he can see nothing through the small hole, but one night, through the peeping hole, he saw a girl named Ikuno Emiru, a perverted voyeur who ropes him into her peeping fetish… But each winds up getting more than they bargained for.