Hat Off When You Kiss (1971)

Fred works as an engineer and a test driver at a car company. His girlfriend Petra is a car mechanic - actually an ideal combination. However, the old-fashioned Fred is less than thrilled about his girlfriend’s "male profession". In his opinion, the masculine job damages her femininity. Since Petra is unwilling to give up her beloved job for such stupid concerns, there is a lot of friction between them. It is not until Petra turns the heads of all the men at a fair that Fred realizes how absurd his objections really are.