The Higher Regional Court of Hamm has specified the requirements for joint concern custody of non-married parents
Press release from November 16, 2016
In accordance with § 1626a para. 2 sentence 2 German Civil Code the initial setup of a common parental custody may not contradict the child's well-being. This requires a sufficiently viable social relationship between the child's parents, a minimum degree of agreement between them and their basic ability to reach a consensus. On the other hand, the sole custody of the child’s mother shall persist if the parents cannot communicate with each other and the child would be significantly burdened by a common parental care.
More detailed informations you will find in the Press release.