Das doppelte Lottchen (1950)

Two nine-year-old girls—rude Luise Palfy and respectful shy Lotte Körner—meet on a summer camp. Apart from their different hair-do, they look alike. They have never seen each other before, but soon find out that they are identical twins. It turns out that their parents divorced, each keeping one of the girls. They decide to trade places at the end of the summer. Lottie curls her hair, Lisa braids hers, and both go off to where they have never been before. The adventure begins.