Hello. I would be grateful for some advice about the following situation. About 5 years ago, I bought a one-bedroom apartment (with tenant) in Berlin. I had no problem with him until this August when I discovered that he had vacated the apartment and sub-let it (without my permission) to a couple with a young child. I understand that he plans to sub-let the apartment until October next year when his daughter, who is going to university, will occupy the apartment. I am angry about this and want to cancel his contract. However, as far as evicting the sub-tenants is concerned, the situation is tricky because of the young child. If I had to go to court to evict the sub-tenants I do not think that a judge will agree to an eviction where a young child is concerned. So, I am wondering if it would be possible to cancel the tenant's contract and at the same time renegotiate a new rental contract with the sub-tenants? Does anybody know is this would be permissible (and legal)?