They really look like 60's posters. I just included the 50's because some of the posters are actually from the late 50's. In fact, the left one you linked adver

They really look like 60's posters. I just included the 50's because some of the posters are actually from the late 50's. In fact, the left one you linked advertises an event happening on "dienstag, 5. mai 1959". The right one seems to be from 1959 too but I'm not sure.