Does the person issuing the warning letter have to provide evidence of authorship before the court? This question regularly arises in copyright law practice if the party issuing the warning denies authorship and requests further evidence. A recent decision(Regional Court Frankfurt, decision of March 10, 2026, Ref.: 2-06 O 41/26) shows that no schematic standards apply in this respect. Rather, the decisive factor is what information the warning letter already contains, what specific doubts are raised and what form of prima facie evidence is reasonable and sufficient at the respective stage of the proceedings.

This question is particularly relevant in practice in copyright law. In contrast to other intellectual property rights, it is often not easy to derive authorization from public registers. Whether someone is the author of a work regularly depends on the actual circumstances of the creation process. Accordingly, disputes often arise in pre-litigation proceedings as to whether and to what extent this authorization must be proven.

Why is the question of proof of authorship so important?

The copyright warning is intended to put the person being warned in a position to actually and legally examine the asserted infringement and to decide on this basis whether to accept the claim or reject the accusation. This also includes the question of who is actually entitled to assert the claim. Legitimization is therefore a central component of every copyright claim assessment.

Particularly in the case of image use, design services, texts or other creative content, it is often not immediately obvious from the perspective of the person being warned who the author of the work in question is. In addition, a user may recognize that a use has taken place, but does not necessarily know who is entitled to the rights concerned. The demand for evidence of authorship or ownership of rights is therefore understandable in principle and in many cases quite obvious from a procedural point of view.

Do supporting documents have to be submitted with the warning letter?

According to the opinion expressed in the decision, there is no general obligation to provide evidence of authorship with the warning letter. The person issuing the warning must provide sufficiently specific details of the infringed party and the infringement complained of. However, this does not automatically mean that all facts substantiating the claim must be documented out of court.

This is dogmatically consistent: the warning letter serves to open up a way for the person being warned to settle the dispute out of court. However, it does not replace court proceedings. Therefore, it is generally sufficient if the claim is presented conclusively and the warned party can recognize what the accusation is based on. An immediate obligation to provide evidence would overstretch the requirements for the warning letter and would partly run counter to the nature of the pre-litigation procedure.

Can supporting documents still be requested in individual cases?

Yes, the decision also makes it clear that justified doubts on the part of the warned party are not irrelevant. If the warning party is made aware of specific uncertainties regarding its justification, it may be obliged to provide further explanations or suitable evidence. The individual case is therefore decisive.

It is essential that the doubts are raised in a comprehensible and substantial manner. A blanket denial is generally not sufficient. However, if specific questions are asked about authorship or legitimacy, the party issuing the warning letter cannot always simply claim to want to explain this only in court proceedings. Rather, it may be necessary to enable the person being warned to examine the authorization in the first place by providing additional information or suitable means of establishing credibility.

The decision thus confirms a differentiated standard: there is no automatic obligation to provide evidence, but there is certainly an obligation to respond to specific doubts on a case-by-case basis.

Which proofs can be considered?

The court’s statement on the affidavit is particularly interesting. According to this statement, the party issuing the warning letter can in principle also submit an affidavit to prove his authorship. This is of practical importance for copyright law, as authorship often cannot be fully proven by traditional documents.

The creation process of a work is typically an actual process that can often only be made comprehensible by the author’s own declaration, possibly supplemented by witnesses or draft documents. In preliminary injunction proceedings, the affidavit is therefore a particularly obvious means of establishing credibility. It makes it possible to present factual circumstances quickly and in a way that can be used in court without having to provide full proof.

Particularly in the case of photographs, graphics, illustrations or other creative works, the affidavit can therefore be practically the central means of making authorship credible in the short term.

What does this mean for pre-trial practice?

For pre-litigation correspondence, the decision means one thing above all: warning parties are not required to enclose extensive collections of evidence with every warning letter as a precaution. However, they should be prepared to respond objectively and robustly to specific and comprehensible queries regarding authorship.

Conversely, it follows for those being warned that objections to the legitimacy of the claim should be formulated precisely. Anyone who doubts the legitimacy of the person issuing the warning should make it clear where the uncertainty lies and what type of explanation is required for the examination. This creates clarity and increases the chances that the dispute can still be resolved out of court.

Our classification

The decision makes it clear that the submission of evidence of authorship in pre-litigation proceedings does not follow a rigid rule. There is no general obligation to submit all evidence with the warning letter. Nevertheless, the party issuing the warning may be required to respond to specific doubts of the opposing party with additional explanations or suitable means of prima facie evidence.

This is an important point for copyright practice. Active legitimation remains a central point of attack in extrajudicial and judicial disputes. Anyone asserting claims should therefore not only be materially entitled, but should also be able to demonstrate this entitlement in a form that corresponds to the respective stage of the proceedings. Anyone defending themselves against a warning letter should address doubts about authorship or ownership of rights in a concrete and comprehensible manner at an early stage.

In this way, it is possible to prevent the discussion about the legitimacy of the claim from escalating unnecessarily – and at the same time ensure that copyright claims are examined on a reliable factual basis.