Cologne Administrative Court, Ref. 10 K 3833/23, judgement of 03.12.2025
The judgement of the 10th Chamber of the Cologne Administrative Court of 3 December 2025 (Ref. 10 K 3833/23) is equally interesting for two target groups: for those affected who wish to assert their German citizenship via the acquisition of a declaration in accordance with Section 5 StAG - and for colleagues who advise on Section 5 StAG cases with a foreign connection and regularly work at the interface of nationality law, parentage law and private international law.
What exactly was it about?
The claimant (born 1972), a Brazilian national, is the daughter of a Brazilian mother and a German father (deceased 1987). The parents were not married at birth. The applicant initially applied for naturalisation in 2016. While the procedure was ongoing, she made a declaration on 30 January 2023 to acquire German citizenship (acquisition of declaration). The Federal Office of Administration refused; the proceedings have now ended with the case being dismissed.
The plaintiff essentially argued that paternity had been effectively recognised under Brazilian law: the father was registered on the Brazilian birth certificate, there was a written acknowledgement of paternity (1972) and a publicly certified power of attorney to a Brazilian lawyer to make declarations on the birth and recognition under Brazilian law. There was also a (handwritten) declaration of consent from the mother from 2020. The plaintiff wanted the current conflict of laws (in particular Art. 19 EGBGB as amended) to be applied for the validity of the parentage - then Brazilian law would be decisive and the parentage could be established much more easily.
The court did not support this argument.
The legal pivotal point: Section 5 StAG refers to an acknowledgement of paternity „in accordance with German law“
The acquisition of citizenship by declaration pursuant to Section 5 (1) StAG is intended to correct historical discrimination: Under the old law, children of German fathers and foreign mothers born out of wedlock could not automatically acquire German citizenship by descent. With Section 5 StAG, the legislator has opened up the possibility of subsequent acquisition by declaration.
But: Section 5 para. 1 sentence 2 StAG refers (via the corresponding application of Section 4 para. 1 sentence 2 StAG) to a central requirement: If only the father was German at birth and recognition/establishment is necessary to establish parentage under German law, then a recognition or establishment of paternity „effective under German law“ is required - and the recognition must have been initiated (or the legal proceedings must have been initiated) before the age of 23.
What is important about this judgement is how the court understands the phrase „in accordance with German law“: This does not only mean German substantive law (i.e. descent law according to the Civil Code), but also the German conflict-of-law rules of private international law in the Introductory Act to the Civil Code.
This means that in § 5 StAG cases with a foreign connection, the first question that practically always arises is: Which conflict of laws is applicable in terms of time - the current or the earlier one?
Why the current EGBGB (Art. 19 ff.) does not help here: Art. 220 EGBGB and „completed transactions“
The court refers to the transitional provision of Art. 220 para. 1 EGBGB: The former private international law applies to „transactions concluded“ before 1 September 1986. In the case of the parentage of illegitimate children, the date of birth is taken as the basis - according to the lineage (also characterised by civil law). If the child was born in 1972 (as is the case here), this is a completed process; therefore, it is not Art. 19 EGBGB new version that is relevant, but the situation at that time under the EGBGB old version.
The plaintiff could therefore not successfully argue that Art. 19 EGBGB (habitual residence of the child) should be applied simply because this provision would be more favourable today. The court rejects a „retroactive“ application of the current conflict of laws rule - precisely because Art. 220 EGBGB expressly regulates the temporal connection.
Which legal system was then decisive? Maintenance statute, home law of the father - and German parentage law (old version).
At that time, the old EGBGB did not contain an explicit conflict rule for the parentage relationship of an illegitimate child to the father. According to case law, the maintenance statute is used as a basis in this respect: According to Art. 21 EGBGB old version, the father's maintenance obligation was governed by the law of the state to which the mother belonged at the time of birth. If German maintenance statute is relevant, German law also applies to the determination of paternity; otherwise the father's home law is decisive.
In the specific case, this led to the application of German substantive law - despite the Brazilian mother - because the home law of the father in question (German) was decisive at the relevant stage. Consequence: The validity of the paternity acknowledgement depended on the German parentage rules in the old version of the German Civil Code.
And this is precisely where the plaintiff failed.
Why the recognition was not effective under German law (old version): consent not given by guardian (official guardianship), time limits for rectification
According to the legal situation at the time, paternity had to be recognised or established by a court in order to establish the paternal parentage of illegitimate children (Section 1600a BGB old version). The child's consent was required for recognition (Sections 1600c, 1600d BGB old version). In the case of legally incompetent children, consent could only be given by the legal representative.
Critical point (and often overlooked in practice): According to the concept at the time, the legal representative for this consent was not simply the mother. Rather, according to Section 1706 No. 1 BGB (old version), a carer was responsible (usually an official guardianship, in practice often via youth welfare office structures). The court emphasises that these requirements also apply if the child is living abroad.
In the case of the plaintiff, the co-operation of a guardian was missing - thus the required consent of the child was missing. Whether one refers to the father's entry in the Brazilian birth certificate (1973) or to the written acknowledgement and authorisation (1972), no valid acknowledgement of paternity was established under the old version of German law without the consent of a carer.
The mother's later „consent“ from 2020 did not help - for two reasons: It was neither given in the required form nor in good time, as the plaintiff was already 48 years old at the time. The court also emphasised that it was only possible to obtain consent within a relatively short period of time (six months from notarisation) in accordance with Section 1600e (3) BGB (old version). The court expressly does not follow the view that, in the case of children born abroad, this period only begins to run when the child enters the German legal sphere or comes of age. Reasoning: The purpose of the short time limit is legal certainty; a „postponement until the child comes of age“ in the case of permanent residence abroad would be incompatible with the purpose of the norm and would have required a clear legislative decision.
Outcome: No acquisition of a declaration, action dismissed. The plaintiff is ordered to pay the costs. Value in dispute: EUR 10,000.
What does the judgement mean for those affected?
-
§ Section 5 StAG is not „automatic“, but stands and falls with the establishment of parentage under German law - including private international law. Those who only focus on the (often well-documented) recognition abroad easily overlook the fact that German courts and the Federal Office of Administration require recognition „in accordance with German law“.
-
For those born before 1 September 1986, the transitional law is decisive. The hope that today's (more favourable) conflict-of-law rules such as Art. 19 EGBGB (new version) will help can be deceptive because Art. 220 EGBGB regularly refers back to the old law.
-
Particularly tricky are constellations in which, under old German law, the involvement of a carer/legal guardian was required for consent. This „historical“ hurdle can often no longer be practically repaired decades later.
What does the judgement mean for legal practice?
For colleagues, the judgement is a good example of how to examine and process Section 5 StAG cases in a structured manner:
Firstly: Timeline and key dates. Date of birth, date of recognition, possible notarisation, age of 23. In addition, the cut-off dates under conflict of laws (1 September 1986) and the question of whether a „completed process“ exists.
Secondly: conflict of laws before substantive law. Do not start with Art. 19 EGBGB new version, but first examine Art. 220 EGBGB and then clearly derive the connection at that time (here via maintenance statute/home law).
Thirdly: take German parentage law (old version) really seriously. It is not about „mere formalities“, but about the constitutive requirements of legal parentage under German law at the time (in particular consent requirements, legal representation/guardian, catch-up periods).
Fourthly: Expectation management and alternatives. If Section 5 StAG fails due to recognition „according to German law“, a classic naturalisation (e.g. according to Section 10 StAG) or another legal status path may be the more realistic approach, depending on the residence biography. The mandate is then less „descent law backwards“ and more about shaping the future of residence and naturalisation law.
Classification: Why this judgement is so often relevant in consulting practice
This group of cases is by no means exotic: many of those affected have fully effective acts of recognition abroad (birth certificate, notarised powers of attorney, acknowledgements) that are undisputed in their country of origin. In certain years, however, German law is linked to additional elements that are historically based and appear difficult to convey from today's perspective. The judgement shows: The courts do not resolve this tension via a „teleology“ of Section 5 StAG, but stick to the system of referring to „German laws“ - including transitional and conflict of laws.
Note: This article is intended to provide general information and does not replace legal advice in individual cases. The specific file situation, the dates and the relevant parentage and conflict-of-law rules at the time are always decisive.
