Honey, I wish it was that easy. Each letting contract these days has a special clause that the person is not suppose to run any business on the premises of the apartment. I can contest the clause regarding "not doing anything immoraly or against the law", as I am perfectly aware I am not breaking any laws myself with my independent escorting. But the business clause is very powerfull and if I would refuse to move, it will come in front of the court where of course I am not going to the winning part, even if I would be, I don't think I would like that much publicity and no clients will ever visit me as the discretion of my place will be compromised.
Also, the law is quite clever here. Makes anybody who knowingly "profit" from escorting / prostitution to be themselves in the position of breaking the law (as they get money out of my for my rent). So, once the letting agency / management agency knows what happen, they will be themselves liable in the face of the law, even if I am not.
This rather clever but pety system makes it harder for us to stay longer in once place and to avoid pathetic complaints like the one I just had.