According to German law, the author is not obliged to have his rights exercised by a collecting society. However, if he decides to do so, he will suffer the consequences of Section 11 (1) of the Perception Act. According to this, the collecting society is obliged to grant the rights exercised by it to anyone on request as simple rights of use under reasonable conditions. The author is therefore basically not subject to any contractual obligation. However, if he avails himself of the help of a collecting society to exercise his rights, then the obligation to contract, to which the collecting societies are subject according to Section 11 I of the Perception Act, also has an indirect effect to his disadvantage. This means that the author loses the power to decide who is allowed to use his works and who is not. The present work examines the question of whether the obligation to contract under Section 11 of the Perception Act applies as limitlessly as the wording of the provision suggests, or whether exceptions are permissible under certain circumstances in the interests of the author or the collecting society.