Warning letter over an unlabelled AI image: what now?

Research as of 1 October 2026. This guide is for the case where a German warning letter (Abmahnung) arrives because an AI image in your store is shown without a label under Art. 50(4) of the EU AI Act. It is written for stores that sell to customers in Germany. As of 30 September 2026, no such warning letter is publicly known (enforcement tracker). How a warning letter works in Germany, what it must contain and what it may cost is, however, already set out in the German Act Against Unfair Competition (Gesetz gegen den unlauteren Wettbewerb, UWG). The provisions are quoted from the German text retrieved on 1 October 2026 from gesetze-im-internet.de (UWG as last amended by Art. 6 of the Act of 12 May 2026); the English wording is an unofficial translation. At one central point it has not been decided how these rules apply to AI labels; the guide says where. For the full picture, see Article 50 of the EU AI Act.

Check first: do not sign, do not ignore

In German unfair competition law, a warning letter is a demand to stop a specific practice, usually with a pre-drafted cease-and-desist declaration (Unterlassungserklärung) and a deadline. Section 13(1) UWG describes its purpose: whoever has an injunctive claim “should” send a warning letter before going to court and give the other party the opportunity to settle the dispute “by giving a cease-and-desist undertaking backed by an appropriate contractual penalty”.

That leads to two mistakes you should avoid:

• Signing unchecked. With the cease-and-desist declaration you commit yourself for the future, usually with a contractual penalty (Vertragsstrafe) for every further infringement. Whether a penalty may be demanded at all, and how far the declaration has to reach, depends on the sender and on the complaint (see below).
• Ignoring it. If you do not respond, the sender may go to court. For injunctive claims under the UWG, Section 12(1) UWG makes preliminary injunctions easier: they can be issued “even without setting out and substantiating the conditions referred to in Sections 935 and 940 of the Code of Civil Procedure”.

Section 13 UWG sets no specific deadline; the deadline is in the letter. Check in this order:

1. Deadline. Put it in your calendar straight away. If it is too short to bring in a lawyer, ask for an extension before it expires.

2. Sender. Who can claim an injunction is set out in Section 8(3) UWG:

With a competitor, it is worth asking whether it really sells comparable goods to a meaningful extent. With an association, whether it is on the list.

3. Mandatory content. Under Section 13(2) UWG, the warning letter must state “clearly and comprehensibly”:

1. the name or company name of the sender and, if represented, of the representative,
2. the conditions of standing under Section 8(3),
3. whether and in what amount reimbursement of costs is claimed and how it is calculated,
4. the infringement, stating the actual circumstances,
5. in the cases of Section 13(4), that the claim for reimbursement of costs is excluded.

If something is missing, it affects the costs. Under Section 13(3) UWG, the sender can only claim reimbursement “insofar as the warning letter is justified and meets the requirements of subsection 2”. Conversely, under Section 13(5) UWG you can claim your own costs of defence insofar as the warning letter is unjustified, does not meet the requirements of subsection 2, or claims reimbursement contrary to subsection 4. This counterclaim is capped at the amount the sender itself claims, and for an unjustified warning letter it is excluded if the sender could not recognise at the time that it lacked a valid claim.

4. The complaint itself. Which images are named, on which pages, on which date? Is the image AI-generated or AI-edited, and does it look real? Not every AI image is a deep fake within the meaning of Art. 50(4) AI Act; the distinction is explained in Which images in your store need an AI label?. Check also what the sender relies on: the missing label (Section 5a UWG, withholding material information; whether Art. 50 is also a market conduct rule under Section 3a UWG has not been decided) or the image showing the product differently from what is delivered (Section 5 UWG, misleading practice). As the next section shows, this can matter for the costs.

What can a competitor demand, and what an association?

For costs and contractual penalties, the UWG distinguishes by sender:

The wording of the two exceptions for competitors (own translation):

Section 13(4) UWG: “The claim for reimbursement of the necessary expenses under subsection 3 is excluded for those entitled under Section 8(3) No. 1 in the case of 1. infringements of statutory information and labelling obligations committed in electronic commerce or in digital services within the meaning of Section 1(4) No. 1 of the Digital Services Act [Digitale-Dienste-Gesetz] or 2. other infringements of Regulation (EU) 2016/679 […]”

Section 13a(2) UWG: “The agreement of a contractual penalty under subsection 1 is excluded for those entitled under Section 8(3) No. 1 on a first warning letter for infringements under Section 13(4) if the recipient usually employs fewer than 100 people.”

Three details:

• No size threshold in No. 1. In the statutory text, the threshold of 250 employees appears only in No. 2 (data protection). For the contractual penalty, the 100-employee threshold of Section 13a(2) applies.
• “Telemedien” is the old wording. Older texts still quote “in telemedia” (in Telemedien); the current version refers to digital services under the German Digital Services Act.
• Associations are not covered. Both exceptions apply only to those entitled under Section 8(3) No. 1. The Higher Regional Court of Hamm referred to the legislative materials: the other parties entitled “should continue to have the option […] of demanding, to settle the dispute, a cease-and-desist declaration backed by an appropriate contractual penalty” (order of 6 February 2024, 4 W 22/23, citing Bundestag printed paper 19/12084, pp. 33 f.).

In the same order, the Higher Regional Court of Hamm decided, for a missing unit price in an online store, that a business usually employing fewer than 100 people that stops the infringement after a competitor’s warning letter and gives a cease-and-desist declaration without a penalty does not give cause for court proceedings. That is one higher regional court’s decision on the Price Indication Ordinance (PAngV), not on AI labels.

Does a missing AI label fall under Section 13(4) No. 1 UWG?

Not decided. No court has yet ruled whether a breach of Art. 50(4) AI Act is an infringement of a “statutory information and labelling obligation” within the meaning of this provision (as of 1 October 2026). The following assessment is this guide’s reading, not settled law.

Arguments in favour:

• Art. 50(4) AI Act requires deployers to “disclose that the content has been artificially generated or manipulated”. In substance that is an information obligation, and the regulation itself refers in Art. 50(7) (as amended by Regulation (EU) 2026/1744) to the “labelling of artificially generated or manipulated content”.
• The infringement happens in an online store, i.e. in electronic commerce.
• According to the legislative materials, the obligation does not have to be one that applies specifically to online retail; it is enough that the infringement occurs there. The Higher Regional Court of Hamm applied the provision on that basis to a missing unit price (order of 6 February 2024, 4 W 22/23, citing Bundestag printed paper 19/12084, p. 32).
• According to the same order, the fact that, following the Federal Court of Justice (Knuspermüsli II, judgment of 7 April 2022, I ZR 143/19), a breach of an information obligation relating to commercial communication is assessed under Section 5a UWG rather than Section 3a UWG does not prevent Section 13(4) from applying.

Arguments against, or open:

• The Higher Regional Court of Cologne refused the cost exclusion in a case where a breach of a price indication rule (Section 11(1) PAngV) was at the same time misleading under Section 5 UWG, and read the provision narrowly for such cases (judgment of 27 March 2026, 6 U 77/25, no appeal on points of law admitted; the court cites Sosnitza, GRUR 2021, 671, 673, and Omsels/Zott, WRP 2021, 278, 285). If an AI image shows the product differently from what is delivered, that is a separate misleading practice under Section 5 UWG; on this line, the exclusion then does not help.
• The Cologne court also argued that a cost exclusion would weaken the enforcement of the EU Unfair Commercial Practices Directive, on whose Article 7 Section 5a UWG is also based. Whether that reasoning also covers cases based on Section 5a UWG alone is open.
• No court decision on the labelling obligation under Art. 50(4) AI Act is known (as of 30 September 2026), neither on the cost exclusion nor on whether a missing label is unfair at all.

What this means for you: if a competitor demands costs or a contractual penalty, this is the first point your lawyer should examine, with both decisions in view. Do not rely on the exclusion applying for certain, and do not assume either that costs and a penalty are automatically owed.

How do you recognise an abusive warning letter?

Under Section 8c(1) UWG, asserting a claim is inadmissible “if, taking into account all the circumstances, it is abusive”. Subsection 2 lists cases in which abuse is to be assumed “in case of doubt”:

1. The warning letter mainly serves to create a claim for reimbursement of costs or for a contractual penalty.
2. A competitor sends warning letters for a substantial number of infringements of the same provision and the number is out of proportion to its own business, or it can be assumed that it does not bear the economic risk of its action itself.
3. The value in dispute is set unreasonably high.
4. Obviously excessive contractual penalties are agreed or demanded.
5. The proposed cease-and-desist undertaking obviously goes beyond the infringement complained of.
6. Several infringements that could have been raised together are raised in separate warning letters.
7. Where several parties are responsible, the claims are not asserted together without good reason.

A single indication is not yet abuse; what counts is the overall circumstances. If there is abuse, you can claim the costs necessary for your defence under Section 8c(3) UWG.

What you do right away

1. Note the deadline, keep the documents. The letter, its enclosures, the envelope or email with the date of receipt.
2. Label or replace the images concerned. An AI image that looks real gets a visible label on the image (Art. 50(4) and (5) AI Act). If the image shows the product differently from what is delivered, replace it: a label does not cure a misleading image. Check places the letter does not mention too, such as collection images, the home page, marketplaces and ads.
3. Record the state. For each image complained of: a dated screenshot of the page before and after the change, your decision (labelled, replaced, or not a deep fake, with a short reason) and, where known, the tool and creation date. Under the Commission guidelines, deployers should also be able to demonstrate to market surveillance authorities how they meet the obligation (C(2026) 5054, para. 148, for deployers who have not signed the code of practice). What belongs in that record is covered in Who enforces the EU AI image labelling rule in your store?. An app such as Easy AI Act Image Labels reads provenance markers on the original file and records your decisions per image; such a log does not show that images without a marker are not AI images.
4. Give a cease-and-desist declaration only after review. Have it checked whether the pre-drafted declaration goes beyond the actual complaint, whether a contractual penalty may be demanded at all (Section 13a(2) UWG) and whether its amount is reasonable. Under Section 13a(4) UWG, if you promise an unreasonably high penalty you only owe a reasonable amount; if only a penalty without a specified amount has been agreed, you can refer a dispute about the amount to a conciliation board (Section 13a(5) UWG). Whether you give the declaration as drafted, in narrower form or not at all is best decided with a lawyer.
5. Bring in a lawyer. Ideally one experienced in German unfair competition law. They will check standing, mandatory content, costs, penalty and abuse. If the warning letter is unjustified, incomplete or abusive, counterclaims under Section 13(5) or Section 8c(3) UWG may be available.

Which cases are known?

As of 30 September 2026, no warning letter over a missing label on an AI image is publicly known, nor any court ruling or administrative proceedings on it, in the EU or in Switzerland. The search method and the monthly status are kept in the enforcement tracker. Warning letters are often not published, so “none known” does not mean there are none.

The route is open nonetheless. In its guide on AI labelling (version 2.0, 29 July 2026), the Wettbewerbszentrale writes that, in its view, breaches of the AI Act “can also be unfair competition under the UWG, so that competitors and associations can assert injunctive claims where fair competition is affected” (own translation). Since 28 July 2026 it has operated its own complaints desk for AI. If a case becomes known with a verifiable source, the tracker will include it and this guide will refer to it.

And in Austria?

Sections 13 and 13a of the German UWG do not apply in Austria. The Austrian Unfair Competition Act mentions warning letters only in Section 7a “Abusive warning letter”, in force since 27 September 2026 (Section 44(16)): whoever sends abusive warning letters can be sued for an injunction and, if at fault, for damages, and has no claim to reimbursement of the costs of the warning letter. Abusive there means a larger number of warning letters with very similar content, no or hardly any lawsuits, and mainly the aim of generating income. Warning letters from the bodies named in Section 7a(4) and (5) are not covered. The Austrian act contains no rules on mandatory content, cost exclusion or contractual penalties like those in Germany (version of 1 October 2026). What else applies there is explained in Labelling AI images in Austria.

In short

Check a warning letter over an unlabelled AI image first: deadline, sender, mandatory content under Section 13(2) UWG and the complaint itself. Then label or replace the images, record the state with a date, and give a cease-and-desist declaration only after a lawyer has reviewed it. If a competitor sends the letter, reimbursement of costs and a contractual penalty may be excluded under Section 13(4) No. 1 and Section 13a(2) UWG; whether that applies to AI labels has not been decided, and where the image is also misleading, the Cologne court’s reasoning points against it. These exceptions do not apply to associations.

Status of all information: statutes, decisions and the association list retrieved on 1 October 2026, cases as of 30 September 2026. General information, not legal advice in an individual case.