Keyword Advertising and Trademark Law

Higher Regional Court of Düsseldorf: Judgment from August 7, 2025 – File No. 20 U 73/34

Visibility is a central success factor in online commerce. Many providers use keyword advertising for this purpose: Specific search terms (sometimes also brand names) are used so that their own offers appear for relevant search queries. The Higher Regional Court of Düsseldorf ruled on August 7, 2025 (File No. 20 U 73/34), that using a third-party brand as a keyword-based search criterion does not necessarily constitute a trademark infringement – provided that consumers can easily recognize that the displayed offer does not originate from the trademark owner and is not original merchandise.

The decision aligns with the trend in European and German case law: The decisive factor is not justthat a third-party brand name is used as a search term, but whether this impairs a trademark-protected function of the brand – particularly the origin function.

What does keyword advertising mean in a legal context?

Keyword advertising refers to the use of specific search terms to display advertisements or product listings on search engines or online marketplaces. This often occurs “invisibly” in the background (e.g., through stored search terms, tags, or booking-based ad mechanisms). Unlike visible use in ad text, the brand name does not necessarily appear in the visible offer but can still guide discoverability.

It becomes legally relevant particularly when a protected trademark of a third party is used as a keyword. Trademark law protects not only the sign itself but also its functions in the market.

The Dispute: Compatible Accessories Instead of Original Products

The judgment was based on a typical online trade conflict: The plaintiff manufactured vacuum cleaners and accessories under a well-known brand (“A”). The defendant offered accessories compatible with the “A” brand devices on a large online trading platform—specifically vacuum bags. In her offer, according to the details of the case, she clearly indicated that it wasnot original products of the trademark owner.

When searching for the brand name “A,” only the defendant’s offers page appeared on the platform, according to the plaintiff’s presentation. The plaintiff derived from this the allegation that the defendant had invisibly stored the brand name “A” as a keyword to capitalize on the brand’s popularity, thus violating trademark law.

Legal Question: Is Keyword Use Sufficient for Trademark Violation?

The Higher Regional Court of Düsseldorf clarified: Using a third-party brand as a keyword can generally constitute atrademark use. However, this does not automatically imply a trademark infringement. What matters is whether a protected trademark function is impaired by the use.

The focus is on theorigin function: A trademark should inform consumers from which company the product originates. If the audience is led to believe that the offer comes from the trademark owner or there is an economic connection (e.g., licensing, distribution partnership), this can establish a trademark infringement.

Moreover, depending on the situation, other functions could be affected (e.g., quality, advertising, or investment functions). In practice, however, the question of misleading origin is regularly the crucial test stage.

Why the Higher Regional Court of Düsseldorf Dismissed the Lawsuit

The Higher Regional Court of Düsseldorf dismissed the lawsuit. The court adhered to established case law, whereby users expect that a brand search on search engines and marketplaces will not exclusively display the brand owner’s original products but also:

• Accessories,
• Compatible products,
• Alternatives from other providers.

In the specific case, it was added that the defendant hadclearly not labeled the goods as original. Therefore, it was readily apparent to the average user that the vacuum bags did not come from the trademark owner but were merely suitable for his devices. According to the Senate’s opinion, there was no relevant risk of confusion or misleading origin; the origin function of the trademark was preserved.

Noteworthy: Whether the defendant actively booked/used the brand name as a keyword or whether the platform algorithmically generated the hits ultimately remained open from the court’s perspective – because, in any case, there was no impairment of function.

What does this mean for online retailers and platform providers?

The decision shows that keyword advertising with reference to third-party trademarks is not inherently impermissible. What is practically decisive is the specific design of the ad or offer and the overall impression on the average internet user.

Important guidelines from the decision:

• Clear origin separation: It must be recognizable that the offer does not originate from the trademark owner.
• Clear labeling for compatible products: Terms like “compatible with,” “suitable for” should be used in such a way that no originality is suggested.
• No misleading about economic connections: Indications suggesting a partnership, authorization, or license are critical.
• Overall impression counts: What matters is not just a single word, but the ad/product page in its entirety (headline, images, brand logos, description, terms and conditions elements, seller name).

Supplementary legal notes (for more legal security)

For a legally secure classification, other areas of law besides trademark law should be considered, depending on the individual case:

• UWG (Unfair Competition Law): Even if there is no trademark infringement, misleading advertising (e.g., about “original,” “OEM,” “authorized”) can be problematic from a competition law perspective.
• Use of brand logos and product images: Even if mentioning the brand for compatibility description may be permissible, the use of logos, protected product photos, or layout elements (copyright/design law) must be separately examined.
• Platform rules: Regardless of the legal situation, marketplaces may impose stricter guidelines on the use of trademarks, keywords, or “compatibility claims.”

Practical tip: For compatible products, it is worthwhile to use a standardized, clear formulation such as “Suitable for vacuum cleaners of brand A” and a clearly visible note “not an original product.” A design that suggests additional proximity to the trademark owner (e.g., by using the brand logo in the title image) increases the risk.

Conclusion

The judgment of the Düsseldorf Higher Regional Court dated August 7, 2025 (Ref. 20 U 73/34) confirms: Keyword advertising using third-party trademarks can be permissible if the origin function of the brand is not impaired. What matters is whether consumers can easily recognize that the offer does not come from the trademark owner and that no original goods are being advertised. Therefore, those offering compatible goods should particularly ensure clear, unmistakable labeling to avoid confusion and misleading risks.

Note: This article is for general information purposes and does not replace individual advice in specific cases.