Das ausgefüllte Leben des Alexander Dubronski (1967)

The municipal gasworks are equipped with ultra-modern electronic booking machines. Lothar Krake, a small employee, is working on such a monster and makes a typo. He doesn't dare admit the mistake for fear of losing his position. With the wrong name, he creates a new customer named Alexander Dubronski, for whom over time Krake manufactures a life of unimagined proportions. Krake lets him live with him, gets him an extra gas meter and one day even writes his memoirs. Money rolls in, but Krake is overwhelmed by the inevitable complications. (via 3sat)