1. The prohibition of issuing rules having retrospective effect, which were developed first and foremost for the state legislator, are applicable mutatis mutandis to a sports federation such as FIFA, because, firstly, this prohibition is an expression of a general legal principle which is not limited to the state legislator. Secondly, insofar as FIFA, as a monopoly federation, is exercising autonomy in issuing regulations and is shaping the world of football, FIFA is acting in a manner that is comparable to a state legislator.