I confess I didn’t know the true meaning of the phrase on the sign. I kew the literal stranslation, but thought it was not a promise of eventual freedom, but an insult to the Jews imprisoned there. In the sense of, you will work, instead of engage inusury or whatever other imagined sin.
“...but an insult to the Jews imprisoned there.”
To ALL imprisoned there; not just the Jews.
That comes from the era of serfdom in Germany. If a serf could live for a year in one of the free cities, he was no longer bound to his lord. Of course, he had to do some kind of paid labor to survive in a city for a year, so “Work makes you free.” The same idea is found in “City air makes a free man.”