Franzie knows nothing about the concept of the wall and about the trespassing rules. However, in the first scene of the film she walks on foot, and then hitchhikes towards West Berlin. This would be impossible without passing through GDR in the 80s, because West Berlin was an enclave inside GDR. To remain clueless about how the border functions, Franzie would need to take a plane to get to West Brrlin.