I can honestly say I have never watched a German comedy before (Excepting Goodbye Lenin), but this was way better than expected. It's everything Bad Teacher could have been and more.
Firstly, it's genuinely funny - petty criminal becomes substitute teacher sounds weak but here the relationships and the script have a lot of zing and deliver.
Even though the arc is fairly by the numbers, the plot detailing is excellent, with fresh siutations and a strong romantic subplot. The cast are all on point and very likable, particularly the stars. All in all we liked it a lot - it's fun, consistently funny, has heart, and is definitely one of the better comedies of 2014.