Flying Classroom (1954) on Netflix

All is not really well between the boys of Gymnasium and the boys of the six-form High School: sparks fly when they get within 100m of each other! The continuous feud between the pupils is only one of the pleasant alternations, which life brings into the everyday school life. In addition, there are the rehearsals for the school theatre; and there are the secrets around a teacher called 'Justus' and a man called 'Nichtraucher' or the "non-smoker" since he lives in an abandoned non-smoking railway carriage. Moreover, in between all the exciting surprises, a few serious things remain to be done...