§ 51

§§ 42-45 do not apply to tenancies in properties whose construction is financed with index loans according to § 2, nr. 9, in the former law on index-regulated mortgage loans. The same applies to tenancies in properties put into use after January 1, 1989, which are constructed and rented out by landlords subject to the law on real interest tax, provided that the rent is determined according to § 50.