There are some judgments in which the AGG was used as a legal basis.

Administrative Court Frankfurt am Main of 03.12.2007, ref.no.: 9 E 5697/06
Facts of the case: A trans man complained because after passing the selection process for the Hessian police service, he was rejected due to his identity as trans. The state police doctor considered the complainant as not fit for service, as according to regulations, male police officers must have ‘at least one functioning testicle’, otherwise mood swings may occur. Despite submitted reports which consider the probability of mood swing to be very low, the state police continued the rejection. The complainant then brought an action for infringement of § 3 para. 2 of the General Equal Treatment Act (AGG):

Judgment: The Court did not rule in favour of the claimant. Only applicants who, by virtue of their physical constitution, are able to give their full  commitment at all times, are eligible for the police enforcement service. An employer could not be obliged to hire a transsexual candidate with hormone problems. The failure of recruitment did not violate the principle of equality and the prohibition of discrimination. On the contrary, the importance of the police enforcement service provided an objective reason for the different treatment. After the pronouncement of the judgment, the complainant filed a constitutional complaint at the Federal Constitutional Court, which was dismissed without reason.

Federal Labour Court of 17.12.2015, re.no.: 8 AZR 421/14
Facts of the case: The complainant is a trans woman and sues for compensation due to a violation of the prohibition of discrimination, according to the AGG. She applied to the defendant and was invited for an interview. However, in the face-to-face meeting, the defendant perceives the complainant as a man rather than a woman and doubts her gender several times during the interview. Shortly after, the complainant received a rejection letter. The conclusion that the defendant considered the complainant to be transsexual because he did not believe her to be a woman when meeting her and remained sceptical even after, is too short-sighted. He had not known that the plaintiff was transsexual, and therefore, he could not have discriminated against her.

Judgment: The court ruled in favour of the complainant. The complainant is entitled to compensation according to § 15 para. 2 AGG. Trans*identity as such does not specifically belong to the grounds mentioned in § 1 AGG, to which the prohibition of discrimination in § 7 para. 1 AGG refers. However, it can be relevant in the context of the ground ‘gender’ and ‘sexual identity’ pursuant to § 1 AGG, both mentioned in the justification to § 1 AGG. It is not required to fully prove the discrimination, but only to be regarded by the court as predominantly probable.