I recently brought an apartment in Berlin without a mortgage. I now wish to take out a mortgage, but the banks I've spoken say I must have a tenant. I wish to use the apartment myself when I come to Berlin, and also let my friends have use of it from time to time, so I don't want to let it. However, I have to have a tenant to get the mortgage. A German friend has told me she will happily take out a rental contract, which can be shown to the bank, but I assume the banks run checks. Do you know what these checks are? Do they contact the tenants employer and there bank, etc?