Misleading Advertising with Climate Protection

OLG Düsseldorf, Judgment of December 4, 2025 – Case No. I-20 U 38/25

Environmental and climate protection plays a central role for many consumers when making purchasing decisions. Accordingly, companies often use statements such as “climate-neutral,” “CO2-neutral,” or “sustainable” in their advertising. However, such terms are legally sensitive: They can be inadmissible under the Act Against Unfair Competition (UWG) if they create a false overall impression among the target audience or if essential information is missing.

The OLG Düsseldorf confirmed this in part with its judgment of December 4, 2025 (Case No. I-20 U 38/25) for an online offer by an airline. The decision is part of a stricter line of case law concerning environmental advertising claims. The BGH had already made it clear on June 27, 2024 (Case No. I ZR 98/23) that with ambiguous environmental terms like “climate-neutral,” the specific meaning must be regularly explained clearly in the advertisement itself; a mere reference outside the advertisement or only behind a link might not suffice, depending on the setup.

“Flying More Sustainably”: Additional Option in Booking Process

In the case at hand, the airline offered, in the final step of the online booking process under “Additional Options,” the possibility to offset the CO2 emissions of the flight through contributions to climate protection projects for an extra charge (9 euros). The offer was promoted with the following formulations, among others:

“Fly more sustainably. Together we make flying more sustainable. You can now offset the CO2 emissions of your flight by contributing to high-quality climate protection projects.”

By clicking on “Learn more,” users were taken to additional information, including:

“When you offset the CO2 emissions of your … flight, you support … climate protection projects … The future of CO2-neutral flying is just one click away.”

An additional option was offered to support the use of “Sustainable Aviation Fuel” (SAF) with another payment. It was explained that SAF could significantly reduce CO2 emissions compared to fossil aviation fuel (by at least 80 percent).

Lawsuit Due to Misleading: What Consumers Can Expect

The Federation of German Consumer Organisations considered the setup misleading and demanded an injunction. The core reason stated was:

• Consumers might understand the statements to mean that the flight would become entirely climate-neutral with the additional payment.
• In addition to CO2, flying produces other climate-relevant effects (e.g., nitrogen oxides, contrails) that the offered compensation does not cover.
• In this context, the term “sustainable” could be understood as especially extensive environmental relief.

The District Court of Düsseldorf initially dismissed the lawsuit. From its perspective, it was recognizable that the offer related specifically to the compensation of CO2, and complete climate neutrality was not promised.

Decisive Is the Overall Impression on the Average Consumer

The OLG Düsseldorf partly assessed the matter differently and partially amended the judgment. According to the court, it is not only important whether individual statements are correct when viewed in isolation but also primarily what overall impression the advertising creates for the average consumer.

The OLG emphasized, among other things, that terms like “CO2-neutral” and “climate-neutral” are often used interchangeably in everyday language. As a result, a significant part of the audience might get the impression that all climate-relevant impacts of the flight would be offset by the additional payment. This, however, is not the case if the compensation explicitly targets only CO2 emissions and other climate-relevant effects are disregarded.

Consequence: In the OLG’s view, the airline should have clearly and unequivocally pointed out that only CO2 emissions are compensated, and the flight is therefore not completely “climate-neutral.” Such a notice must be placed and worded so that it is perceived in direct connection with the advertisement.

SAF Notice Not Objected

However, the OLG Düsseldorf did not object to the statements about the SAF offer. It was crucial that specific, verifiable information regarding the reduction of CO2 emissions (at least 80 percent) was made, and it was not suggested that complete climate neutrality would be achieved. Additionally, the OLG considered the term “sustainable” in this specific context more as a general evaluative statement, which was adequately qualified by the explained reduction information.

Outlook: Stricter rules from 2026 and growing requirements for “Green Claims”

The OLG did not allow the appeal and pointed out, among other things, that comparable advertising could be problematic under the stricter regulations that will come into effect from September 2026. Regardless of the specific legislative process, the trend is clear: Environmental and climate statements must bemore precise, verifiable, and understandable.

Even today, the UWG particularly stipulates:

• Prohibition of misleading information: Advertising must not contain false or deceptive information (especially § 5 UWG).
• Transparency of essential information: Essential restrictions (e.g., “only CO2, not other climate effects”) must not be hidden (especially § 5a UWG).
• Verifiability: The significance and scope of environmental claims must be reliably demonstrable in case of dispute (e.g., compensation methodology, quality of projects, calculation approach, system boundaries).

Practical advice for legally compliant climate protection advertising

Companies that advertise with climate protection should especially:

• elucidate ambiguous terms (“climate-neutral”, “CO2-neutral”, “sustainable”) concretely (What exactly is being compensated? Which emissions are not? What system boundaries apply?).
• Design hints so that they areperceptible in the immediate advertising context (not “hidden” only after several clicks).
• disclose during compensation whether it is aboutavoidance/reduction orcompensation – and which standards are applied.
• avoid blanket exaggerations when the measure only covers partial aspects (e.g., only CO2 instead of the full climate effect).

The decision shows: Even factually correct partial information can be inadmissible if the overall impact of the advertising creates greater expectations among the audience. Therefore, anyone advertising with environmental claims should formulate especially carefully and understandably.

For the review and design of advertising claims in competition law, we are happy to provide support if needed.