Also long history of french being what different social elites like nobles and intellectuals liked to cosplay, leading to french being kind of a status symbol for being culturally educated
Also I think the more pressing/interesting question is why they don’t teach turkish, since ~every 30th person has a turkish backround
English and French are world languages and open up job opportunities. Turkish is only spoken in Turkey, it isn’t interesting economically and immigration from Turkey to Germany is a one-way street. If you want to learn Turkish that’s cool, but it is and should be optional at school.