In particular, the following similarities (among others) were noted, according to the "Titelschutz Anzeiger":
The author insisted that this was a legal use of the book, because this Pippielotta has a twin sister (as in the book Das doppelte Lottchen) and combines the two stories with a critical reflection upon growing up.
Das dopplete Pippielotta Pippi Langstrumpf Pippielotta Pippilotta a red-headed girl from Sweden a red-headed girl from Sweden with wild braids and Herkulean strength with wild braids and Herkulean strength Krumunkulus pills to keep from becoming an adult Krummeluß pills to keep from becoming an adult lives in the Villa „Kunterbund“ lives in the Villa „Kunterbunt“ has an ape called „Frau Karla vom Dach“ and a horse called "Pferd" (horse) has an ape alled "Herr Nielsson" and a horse called "Kleiner Onkel" (little uncle)
The court begged to differ. Despite the occasional reflection, they deemed the book a plagiarism that needed the permission of the author resp. heirs in order to be published. They did not and will not give permission.
Update: Nadja aus Lübeck writes: Pippi's horse was really called "Pferd" (horse) in Astrid Lindgren's books. It was only for the film that Inger Nilsson came up with the name "Kleiner Onkel" so that the horse would have a proper name.