With Opel and Citroën both being part of the Stellantis group, it is not surprising that techniques, platforms and even models are shared. For example, the Opel Rocks is actually a Citroën Ami and the new Frontera shares its genes with Citroën's C3 Aircross. But did you know that 100 years ago there was also an Opel "inspired" by a Citroën?
Having replaced the Type A with the B2 in the spring of 1921, André Citroën added a second model to the range a year later: the compact 5HP. This model became a success, not only because of its competitive price, but also because of Citroën's clever marketing, which specifically targeted a female buyer group. The 5HP was soon nicknamed P'tit Citron (little lemon) because of the yellow colour in which many models were delivered.
Opel expected that such a model could be a success in Germany, and came up with the 4 PS in 1924. Because of its green body colour, the model was nicknamed Laubfrosch (tree frog). The 4 PS was the first German car to be built on an assembly line - a principle Opel had copied from Citroën. And there were more similarities. Not only did the bodywork look very similar to that of Citroën's 5 HP, but the technology also seemed copied from its French rival. The wheelbase was exactly the same and under the bonnet of the Opel was, like on the Citroën, a small water-cooled side-valve engine with four cylinders. Only the displacement was different.
Citroën sued Opel for plagiarism and eventually the case went to court. Strangely enough, it was not Citroën, but Opel that won the case! On 25 June 1927, a German court ruled that, while some striking similarities between the two models were indeed visible, it could not be proven that Opel had copied Citroën's 5HP, as differences could also be seen. As an example, the shape of the radiator was mentioned. Opel was therefore allowed to continue producing the Laubfrosch. But in Germany, ‘Dasselbe un Grün’ (the same but in green) has been a well-known expression ever since to indicate that something is not actually different at all.
