Subtenants are people who use a flat or parts of a flat that have been rented by another person, that is, the so-called main tenant. Those who live as subtenants, therefore, have no rental contract with the flat owner. For this reason, the contractual parties are referred to as subletters and subtenants. If the right of use (main tenancy) of the subletter is dissolved, the subletter must inform the subtenant of this immediately. The right of use of the subtenant expires with the end of the main tenancy agreement, although this is not clearly regulated by law. Under the coverage of the Act on Tenancy Law (MRG), bans on subletting are only legally effective in the main tenancy agreement if there is an important reason against subletting (e.g. total subletting or subletting for a disproportionately high return). If the subletting fee exceeds the main rent by more than 50%, the subtenant may claim back the excess amount.