We recommend to ask for a rent which doesn't exceed your own costs, so that you don't make a profit from the sub-lease.
But of course you can demand a sum that covers your effective costs. That includes ancillary costs, such as utilities (electricity and water), TV and radio license fee, internet charges, etc, in addition to the gross base rent.
In theory, you could also apply a surcharge for the furnishings, but this is seldom done in practice because as a private subletter, one's primary objective is to cover, or at least substantially minimize, one's effective rental costs at home during an extended stay abroad.
The fact is that the majority of our providers demand only their effective costs and about a third even less than that. Only a few ask for a surcharge for furnishings.
We don't publish clearly overpriced apartments.
The legal background of this provision is that you can «use» the property you rent, but not «gainfully». In other words, you may not profit from the property you rent – only the landlord is able to do that.
If you sub-let your apartment at a higher rent than you pay yourself, you are profiting from it. At a correct rental price, however, the apartment is let to the sub-tenant «for the use of» – and in legal terms, that makes a difference.
No responsibility is taken for the correctness of this information.