What is a computer program anyway? The effects of CJEU’s judgment in C-159/23 Sony Computer Entertainment Europe

A case about more than just a game

Although the Court of Justice of the European Union (CJEU) has been shaping copyright in the EU for years, it is difficult not to get the impression that the debate about its judgments usually overlooks their impact in the national cases that sparked the preliminary references. However, even if the CJEU does mention it explicitly, under Article 267 of the Treaty on the Functioning of the European Union (TFEU) it is always “up to the national court” that asked a preliminary question to eventually decide the outcome of a given case. On the national level, both parties of the proceedings attempt to extract favourable passages from the CJEU’s response, while the national court must wrestle with applying the fresh interpretative guidance to the established facts. As it sometimes turns out, the devil may be in the technical details, as evidenced by the fate of the case C-159/23 Sony Computer Entertainment Europe. We have already discussed the brief history of the case, the preliminary questions referred by the German Federal Supreme Court (BGH), as well as the opinion of Advocate General Szpunar. This contribution summarizes the 2024 judgment of the CJEU, its effects on not one, but two judgments of the BGH issued on the same day, as well as the potential long-term repercussions.

In short, the case involved software that manipulates content of variables stored in a computer’s working memory when another computer program (or, to be precise, a component of a videogame protected as a computer program) is running. Sony argued that was the way in which Datel, a developer of videogame cheats, infringed the exclusive right from Article 4(1)(b) of the Software Directive. Formally, the case focused on MotorStorm: Arctic Edge; a 2009 racing game remembered probably only by the most avid fans of the PlayStation Portable (PSP) console, which itself was discontinued in 2014. However, it is difficult not to perceive the entire lawsuit as strategic litigation by Sony, aiming to obtain advantageous precedent. Videogame cheats may threaten business models, especially for multiplayer games, so it is not surprising that developers are interested in expanding their legal arsenals. At the same time, we noted that any judgment favourable to Sony would have ramifications beyond game development, so any description of the case as involving only videogames and cheats would be overly simplistic.

The CJEU (almost) follows the AG’s opinion

In his opinion, AG Szpunar advised the CJEU to reject Sony’s arguments. According to him, the content of variables is ‘merely data (…) which the computer produces and reuses when running the program’, so it is not a protected form of expression of a computer program under the 2009 Software Directive (para 48). He also placed strong emphasis on the code-based (‘literal’) expression of the program (para 40), which, if taken strictly, could narrow the space for protecting non-literal elements such as program structure. Finally, AG Szpunar dismissed the arguments for applying the InfoSoc Directive.

The reasoning presented in the judgment of the CJEU is deceptively simple. One would be forgiven for getting an impression that the court considered the issue acte clair and was surprised that a request for preliminary ruling was even necessary. After dismissing on formal grounds the European Commission’s arguments concerning the InfoSoc Directive (paras 25-29), the CJEU went on to summarize the current acquis concerning the scope of copyright protection of computer programs, and particularly the notion of a form of expression of a computer program (paras 31-49). Finally, in a very short passage, the CJEU followed AG Szpunar’s recommendations almost to the letter. It noted that Datel’s software “does not change or reproduce either the object code, the source code or the internal structure and organisation of Sony’s software used on the PSP console, but merely changes the content of the variables temporarily transferred by Sony’s games to the PSP console’s RAM” (para 50). The latter is not a form of expression protected under the Software Directive (para 51). Following this conclusion, there was nothing left to salvage from Sony’s claims. The CJEU departed from AG’s opinion in one detail: it acknowledged for the first time that the Software Directive covers not only code, but also the internal structure and organisation of a computer program.

The case goes back to Germany

On 31 July 2025 the BGH issued judgments in two cases the outcomes of which were influenced by the CJEU’s response. The first case was, obviously, the one which led to the preliminary question (I ZR 157/21, Action Replay II). Here, the application of the interpretation provided by the CJEU was a mere formality. The BGH relied on the unchallenged findings of the Higher Regional Court (OLG) in Hamburg, according to which Datel’s software was only influencing the execution of the programs by changing variables that are generally known to the game, and did not affect the commands of Sony’s game software, nor its internal structure. This could lead to only one outcome unfavourable to Sony.

The second judgment issued on the same day (I ZR 131/23, Werbeblocker IV) revealed that under the formula devised by the CJEU, not all interferences with computer programs at runtime are the same. Here, the dispute was initiated by a publishing company against providers of a browser plugin that blocks advertisements. A modern website is essentially a combination of elements that may be protected under the InfoSoc Directive, elements that are forms of expression of computer programs under the Software Directive (e.g., scripts written in JavaScript), and elements that are neither of those. A web browser uses these components to render, i.e. show, the website to the user. The plugin interfered with this machinery by either preventing the browser from retrieving ads from an external server or preventing such content from being displayed. One way or another, it enabled users to browse websites without advertisements, which in turn interfered with the publishers’ business model. The plaintiff claimed that the plugin interfered with structures that are forms of expression of a computer program, so their unauthorized modifications infringe copyright. The case was dismissed by the Regional Court and the Higher Regional Court in Hamburg. However, quite surprisingly, the CJEU’s decision in C-159/23 Sony did not put a nail in the coffin for the case.

Instead, the BGH reversed the decision and sent the case back to the Higher Regional Court. The core of the dispute at this stage concerned very specific data structures that are generated by a web browser when a given website is visited. The plaintiff argued that such structures, i.e. the DOM (Document Object Model), CSSOM (CSS Object Model) and the Render-tree (that combines DOM and CSSOM to determine what to display) represent translations of the website program into a form that the browser executes, and therefore embody executable instruction sequences attributable to the plaintiff’s program. The BGH held that the Higher Regional Court dismissed these arguments prematurely, because it failed to present a clear definition of the protected subject matter; in particular, failed to examine whether the website program generates executable code in the browser. One of the instructions given to the Higher Regional Court specifically requires taking into consideration that the case may be distinguishable from the one decided in C-159/23 Sony, because unlike in the latter case, the modification does not involve only temporary variables that are mere data, but may instead involve code generated by the plaintiff’s program.

In short, although the BGH did not explicitly endorse a plaintiff-friendly interpretation, it forced the Higher Regional Court to take a far deeper dive into the technical aspects in order to precisely define the subject matter. Although it is not specifically mentioned in the BGH’s reasoning, we may note that the dispute involved more complex data structures that are far easier to access and modify than the variables temporarily stored in the working memory in the videogame scenario. Despite the seemingly technologically neutral language of the Software Directive, as well as its German implementation, the outcome of a given case may depend on technical details.

The way ahead

Before the Higher Regional Court in Hamburg writes the new chapter of the ad-blocking case, we may consider the broader effects of the CJEU’s decision in C-159/23 Sony. First of all, the original videogame case and the ad-blocking cases prove that strategic litigation involving copyright is alive and well. In both cases, the works in question were merely vehicles used by the plaintiffs to advance a broader agenda, aiming to protect business models in gaming or online advertising.

Secondly, although the outcome in the Sony case may be seen as a setback for the game developers, the narrow framing of the CJEU’s judgment, essentially dictated by the facts of the case, facilitates distinguishing it from other potential scenarios. Furthermore, videogame developers have other tools at their disposal. In Germany, the practical effects of the dual, or hybrid nature of videogames under EU copyright law (protected both under the Software Directive, and the InfoSoc Directive) were instrumental in a holding against a provider of bots who was unable to invoke the reverse-engineering provisions implementing Article 5(3) Software Directive, because his actions also involved the audiovisual elements of the game. Since making cheats is also likely to involve at least some forms of reverse-engineering, battling their developers with copyright claims may simply require shifts in the litigation strategies.

Thirdly, even after the CJEU’s judgment in C-159/23 Sony, there is still no clear answer as to which artefacts, other than source code or object code in the strictest sense, qualify for protection under the rules applicable to computer programs in the EU. The ad-blocker case is just one practical example of this uncertainty.

Last but not least, the explicit confirmation in C-159/23 Sony that “the internal structure and organisation of a computer program” is a form of expression protected under the Software Directive may inspire new attempts to pursue claims based on non-literal copying. As futuristic as it may be for now, this may be the next frontier of EU copyright dispute involving software, due to the rapid development of AI tools that push the human operators away from writing code as such, while potentially leaving them in charge of the overall architecture.

The post was written as part of a research project funded by the National Science Centre (Narodowe Centrum Nauki), Poland, grant no. 2023/51/D/HS5/00710 (Copyright protection of computer programs in the European Union after three decades).