The Substitute (2007)

Title: Vikaren (Denmark)
Genre: Horror, Sci-Fi, Comedy, Fantasy
Country: Denmark
Language: Danish
Runtime: 93 min
Director: Ole Bornedal
Cast: Paprika Steen, Ulrich Thomsen, Jonas Wandschneider, Nikolaj Falkenberg-Klok, Emma Juel Justesen, Mollie Maria Gilmartin, Josephine Gents, Emma Claudia Sřndergaard

Plot:
6th Grade gets a new substitute teacher. She wants to train the class for an international competition in Paris. But something isn't right. How is she able read kids' minds? Why is she so mean? And how does she manage to convince everyone's parents she is so great when the whole class knows she is really an alien?

http://www.imdb.com/title/tt0478394/