German court revives ad blocker lawsuit against Adblock Plus

Germany's Federal Court of Justice has overturned a 2023 ruling that protected ad blocking software from copyright claims, sending the case back to the Higher Regional Court of Hamburg for fresh consideration. The decision on July 31, 2025, creates new uncertainty around ad blocking legality in Germany's digital advertising ecosystem.

The ruling represents a significant setback for Eyeo GmbH, the Cologne-based company behind Adblock Plus, in its decade-long legal battle with Axel Springer SE. The media conglomerate, which owns brands including Bild and Die Welt, has pursued multiple legal strategies to restrict ad blocking software that reduces advertising revenue across its digital properties.

Technical foundations drive legal arguments

The Federal Court of Justice identified critical gaps in the lower court's analysis of website code protection under German copyright law. According to the ruling, the Hamburg court failed to adequately examine whether browser-processed website code qualifies for copyright protection under Section 69a of the German Copyright Act.

Axel Springer argues that websites constitute computer programs protected by copyright law. The publisher contends that when Adblock Plus blocks or modifies website code in users' browsers, this constitutes unauthorized modification under Section 69c(2) of the Copyright Act and violates reproduction rights under Section 69c(1).

The case focuses on how browsers process website content through virtual machines using bytecode rather than traditional object code. Legal representatives for Axel Springer, Lubberger Lehment, emphasized this technical distinction in their analysis. Browser virtual machines operate through bytecode that creates executable code for computer processors, differing from standard software architecture.

"In particular, the Higher Regional Court did not sufficiently consider Axel Springer's argument that a browser is a virtual machine controlled by a website program as byte code," the law firm stated following the ruling.

Lower court reasoning rejected

The Federal Court of Justice criticized the Hamburg court's assumption that ad blocking technology merely affects "program execution" without touching program substance. The decision outlined fundamental problems with this reasoning, noting the court "arrived at its decision without first establishing important fundamentals."

The Hamburg court had previously ruled that ad blocking software does not violate copyright because it only influences browser-generated data structures rather than modifying the actual website programming. This reasoning distinguished between the original HTML files and temporary browser structures like DOM trees and CSS objects.

However, the Federal Court found this analysis insufficient. The highest court determined that distinguishing between program substance and execution requires clearer definition of the protected code elements and their copyright-qualifying features.

Industry-wide implications emerge

The ruling affects browser applications across the software sector due to shared technical components including HTML5, CSS, PHP, and JavaScript. Lubberger Lehment characterized the case as having "fundamental importance for the entire software industry" because all browser applications utilize these standard web technologies.

Cloud-based applications face particular scrutiny under the court's reasoning. Computer games, standard software packages, and enterprise systems like SAP operate through similar browser-based architectures that could face copyright protection questions.

"This affects all cloud-based applications such as computer games, standard software, SAP, etc. The ad blocker trial will determine whether this future technology is protected by copyright or can be manipulated at will by third parties," according to Axel Springer's legal representatives.

Advertising revenue concerns drive litigation

German publishers report significant financial pressure from increasing ad blocker adoption. Axel Springer has framed the legal challenge as essential for sustainable journalism funding without paywall restrictions.

"It is about the question of whether at all and in what quality online journalism can be offered and used in the future – it is about freedom of information without paywalls. This is fundamental to democracy," Lubberger Lehment stated in response to the ruling.

The publisher has pursued copyright claims after earlier competition law arguments failed. Germany's Supreme Court rejected Springer's initial competition-based lawsuit against Adblock Plus in April 2018, prompting the shift to copyright-focused legal strategy.

Technical complexity creates enforcement challenges

The Federal Court of Justice highlighted technical aspects requiring deeper examination during case reconsideration. Browser engines create complex data structures including Document Object Models and CSS Object Models that translate website programming into visual content.

Axel Springer claims these browser-generated structures represent protected expressions of its website programming. The publisher argues that ad blocking software modifies these structures in ways that constitute copyright infringement rather than legitimate user control over browsing experience.

Eyeo has consistently disputed these characterizations, describing Springer's copyright claims as "almost absurd." The ad blocking company maintains that its software provides users with legitimate control over their browsing experience without violating copyright protections.

European digital advertising transformation

This ruling occurs amid broader changes to European digital advertising regulation. YouTube has expanded ad blocker detection systems globally, while browser developers like Brave implement technical solutions to maintain ad blocking functionality.

Recent German court decisions on digital privacy and consent demonstrate judicial willingness to examine technical aspects of web browser behavior. These rulings establish precedent for detailed technical analysis in digital rights cases.

The advertising industry faces mounting compliance challenges under evolving European regulations, creating additional pressure on traditional revenue models that depend on unrestricted advertising delivery.

Meanwhile, Eyeo has undergone significant strategic changes during the legal proceedings, appointing Douglas de Jager as CEO amid a privacy-focused pivot. The company reduced its workforce by 40% while transitioning from traditional ad-blocking software to comprehensive privacy protection services, signaling broader industry shifts toward privacy-first advertising solutions.

Competition law precedent established limits

Axel Springer's original legal strategy focused on competition law violations, arguing that ad blocking software unfairly interfered with its business model. The German Supreme Court's 2018 decision established that ad blocking does not constitute anti-competitive behavior under existing frameworks.

This precedent forced the shift to copyright-based arguments, which focus on technical modifications to website code rather than market interference. The copyright approach attempts to establish direct infringement of protected intellectual property rather than indirect business harm.

The Hamburg Regional Court initially rejected this copyright strategy in January 2022, determining that ad blocking software does not engage in unauthorized copying or modification of computer programs as defined under German law.

Future proceedings require technical analysis

The Federal Court of Justice outlined specific technical questions requiring examination during renewed proceedings. The court emphasized that determining copyright infringement depends on precise identification of protected code elements and their qualifying features.

Browser-generated bytecode analysis will likely prove central to future arguments. The court must examine whether this dynamically-created code qualifies for copyright protection and whether ad blocking modifications constitute infringement.

The ruling specifically addresses differences between this case and previous software modification disputes. Unlike scenarios involving simple data modification, this case involves potential changes to code generated by website programming itself.

Software industry monitoring developments

Technology companies across Europe monitor this case due to potential precedent affecting browser functionality and user control software. The ruling's technical reasoning could influence future litigation involving browser extensions, content filtering software, and user customization tools.

Enterprise software providers face particular scrutiny given the court's emphasis on cloud-based application similarities. Companies operating through browser-based interfaces may need to reassess their copyright protection strategies.

The case also affects academic and research communities developing web accessibility tools. Software designed to modify web content for disabled users operates through similar technical mechanisms as ad blocking technology.

Timeline

• 2012-2013: Axel Springer initiates legal action against Eyeo GmbH over Adblock Plus interference with business model
• April 2018: Germany's Supreme Court rejects competition law claims, finding no breach of competition regulations
• January 2022: Hamburg Regional Court denies copyright-based injunction request, ruling no unauthorized program modification occurred
• January 2022: Eyeo partners with Factmata to develop Trusted News browser extension
• March 2022: Eyeo launches Trestle ad platform reaching 225 million ad blocker users
• January 2023: Brave browser launches ad network using Adblock Plus business model
• 2023: Higher Regional Court of Hamburg rules in favor of Eyeo, protecting ad blocking from copyright claims
• October 2024: Google Analytics blocking study shows AdBlock Plus as leading blocker 
• July 31, 2025: Federal Court of Justice overturns Hamburg decision, remanding case for reconsideration of technical issues
• July 2025: Eyeo appoints Douglas de Jager as CEO amid strategic privacy pivot
• July 2025: European Commission releases implementation guidance for political advertising rules
• August 2025: Mediavine launches petition demanding AI copyright protections

PPC Land explains

Ad blocking software: Technology that prevents advertisements from displaying on websites by filtering out advertising content before it reaches users' browsers. Popular ad blocking tools like Adblock Plus work by maintaining lists of known advertising servers and content patterns, automatically blocking requests to these sources when users visit websites.

Copyright infringement: The unauthorized use of copyrighted material in ways that violate the exclusive rights of copyright holders. In this case, Axel Springer claims that ad blocking software illegally modifies their website code, which they argue constitutes protected computer programming under German copyright law.

Bytecode: An intermediate form of computer code that virtual machines can execute, sitting between human-readable source code and machine-specific binary code. Browser engines use bytecode to process website instructions, creating a key technical battleground in determining whether ad blocking modifications constitute copyright violations.

Federal Court of Justice: Germany's highest court for civil and criminal matters, equivalent to a supreme court in other legal systems. The court's decisions establish binding precedent for lower courts and carry significant weight in shaping German legal interpretation of emerging technology issues.

Hamburg court: Refers to both the Hamburg Regional Court and Higher Regional Court of Hamburg, which previously ruled in favor of Eyeo GmbH and against Axel Springer's copyright claims. These intermediate courts must now reconsider their decisions following the Federal Court of Justice's reversal.

Website code: The programming instructions that create and control web pages, including HTML markup, CSS styling, and JavaScript functionality. Axel Springer argues this code qualifies for copyright protection as computer programming, making unauthorized modifications through ad blocking potentially illegal.

Browser engines: Software components that interpret website code and render web pages for users, including parsing HTML, executing JavaScript, and applying CSS styles. The technical complexity of how these engines process code has become central to determining copyright boundaries in ad blocking disputes.

Computer programs: Software protected under German copyright law Section 69a, which grants exclusive rights to reproduction, modification, and distribution. The legal question centers on whether website code qualifies as computer programming deserving the same copyright protections as traditional software applications.

Eyeo GmbH: The Cologne-based company that develops and maintains Adblock Plus, one of the world's most popular ad blocking browser extensions. The company has defended ad blocking as legitimate user control over browsing experience rather than copyright infringement against website publishers.

Digital advertising: Online marketing that generates revenue for websites and content publishers through display advertisements, sponsored content, and tracking-based targeting. The case highlights fundamental tensions between publisher revenue models and user desires for ad-free browsing experiences across the internet.

Summary

Who: Germany's Federal Court of Justice ruled in a case between Axel Springer SE (publisher of Bild and Die Welt) and Eyeo GmbH (maker of Adblock Plus), with legal representation by Lubberger Lehment law firm.

What: The court overturned a 2023 ruling that protected ad blocking software from copyright infringement claims, determining that lower courts failed to adequately examine whether website code qualifies for copyright protection under German law.

When: The Federal Court of Justice delivered its decision on July 31, 2025, addressing a case that began over a decade ago with Axel Springer's initial competition law challenges.

Where: The ruling occurred in Germany but establishes precedent affecting browser technology and software copyright protection across European Union member states with similar legal frameworks.

Why: The case centers on whether ad blocking software violates publishers' copyright by modifying website code in users' browsers, with Axel Springer arguing this constitutes unauthorized program modification while Eyeo maintains users have legitimate control over their browsing experience.