Opinion of the Advocate General — ECLI:EU:C:2021:193
Date: 2021-03-10
Language of the case: French
Subject matter: Approximation of laws
Procedure: Reference for a preliminary ruling
Origin: Belgium

Summary C-13/20 — 1 
Case C-13/20 
Summary of the request for a preliminary ruling pursuant to Article 98(1) of 
the Rules of Procedure of the Court of Justice 
Date lodged: 
14 January 2020 
Referring court: 
Cour d’appel de Bruxelles (Belgium) 
Date of the decision to refer: 
20 December 2019 
Appellant: 
Top System SA 
Respondent: 
Belgian State 
  
1. Subject matter and facts of the dispute 
1 The body responsible for selecting and orienting staff for public authorities 
(‘Selor’) has a system for the online submission of applications. 
2 Top System SA (‘Top System’) is a company that develops computer programs. 
To that end, it has designed its own ‘Top System Framework’ (‘TSF’), which is 
based on Microsoft’s ‘.NET Framework’, a suite of tools to assist computer 
programmers, to which TSF adds additional functionalities and makes 
improvements. 
3 To enable Selor to process applications submitted online, Top System created, at 
Selor’s request, various new applications (‘the Selor applications’), including 
‘Selor Web Access’ (‘SWA’), which was released in March 2004. 
4 The Selor applications comprise, on the one hand, ‘tailor-made’ components to 
meet the needs and requirements of Selor and, on the other, components taken 
from TSF. 
EN 
SUMMARY OF THE REQUEST FOR A PRELIMINARY RULING — CASE C-13/20 
 
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5 Top System and Selor have been working together for a number of years. 
Following persistent malfunctions, Selor decided to try to find a solution itself. In 
early 2019, Top System noted that some technical changes had been made to the 
TSF installed with the Selor applications. 
6 By order of 2 February 2019, the President of the Tribunal de Commerce de 
Bruxelles (Brussels Commercial Court, Belgium) granted a petition lodged by 
Top System for an order for saisie-description (confiscation of works infringing 
intellectual property rights). 
7 The appointed expert wrote the following in his report: 
‘It is apparent from an analysis of the data confiscated that Selor did indeed 
decompile Top System’s object libraries in order to recreate the source code. In 
order to do that, Selor very probably used a tool such as ‘Reflector’ (of which 
Selor has at least one copy, on [X’s] work station …. 
We found two examples of specific source code where a change was made on 
19 December 2008. All the files within the folder in question were changed at that 
time. We note that all the references to the binary version of ‘Top System’ have 
been changed to references to the version of the source code added that day.’ 
8 On 6 July 2009, Top System issued proceedings against the Belgian State seeking, 
inter alia: 
– a finding that TSF had been decompiled by Selor in breach of Top System’s 
exclusive rights and that that constitutes the counterfeiting of a work, and 
– an order requiring the Belgian State to compensate Top System on account of 
the decompilation and the copying of the TSF source code. 
9 By judgment of 19 March 2013, the tribunal de première instance de Bruxelles 
(Court of First Instance, Brussels, Belgium) ruled the application unfounded. 
10 Top System brought an appeal before the cour d’appel de Bruxelles (Court of 
Appeal, Brussels), where it pursues its claims. 
2. Provisions at issue 
Council Directive 91/250/EEC of 14 May 1991 on the legal protection of 
computer programs 
11 Article 4 provides: 
‘Restricted Acts  
TOP SYSTEM 
 
3 
Subject to the provisions of Articles 5 and 6, the exclusive rights of the 
rightholder within the meaning of Article 2, shall include the right to do or to 
authorise: 
(a) the permanent or temporary reproduction of a computer program by any 
means and in any form, in part or in whole. In so far as loading, displaying, 
running, transmission or storage of the computer program necessitate such 
reproduction, such acts shall be subject to authorisation by the rightholder; 
(b) the translation, adaptation, arrangement and any other alteration of a 
computer program and the reproduction of the results thereof, without prejudice to 
the rights of the person who alters the program; 
…’ 
12 Article 5 provides: 
‘Exceptions to the restricted acts 
1. In the absence of specific contractual provisions, the acts referred to in 
Article 4(a) and (b) shall not require authorisation by the rightholder where they 
are necessary for the use of the computer program by the lawful acquirer in 
accordance with its intended purpose, including for error correction. 
…’ 
13 Article 6 provides: 
‘Decompilation  
1. The authorisation of the rightholder shall not be required where reproduction 
of the code and translation of its form within the meaning of Article 4(a) and (b) 
are indispensable to obtain the information necessary to achieve the 
interoperability of an independently created computer program with other 
programs, provided that the following conditions are met: 
(a) these acts are performed by the licensee or by another person having a right 
to use a copy of a program, or on their behalf by a person authorised to do so; 
(b) the information necessary to achieve interoperability has not previously been 
readily available to the persons referred to in subparagraph (a); and 
(c) these acts are confined to the parts of the original program which are 
necessary to achieve interoperability. 
2. The provisions of paragraph 1 shall not permit the information obtained 
through its application: 
SUMMARY OF THE REQUEST FOR A PRELIMINARY RULING — CASE C-13/20 
 
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(a) to be used for goals other than to achieve the interoperability of the 
independently created computer program; 
(b) to be given to others, except when necessary for the interoperability of the 
independently created computer program; or 
(c) to be used for the development, production or marketing of a computer 
program substantially similar in its expression, or for any other act which 
infringes copyright. 
3. In accordance with the provisions of the Berne Convention for the protection 
of Literary and Artistic Works, the provisions of this article may not be interpreted 
in such a way as to allow its application to be used in a manner which 
unreasonably prejudices the right holder’s legitimate interests or conflicts with a 
normal exploitation of the computer program.’ 
3. Views of the parties 
Selor 
14 Selor acknowledges that it decompiled part of TSF, the functionalities of which 
were integrated into the Selor application, in order to disable a function that was 
not working correctly. 
15 As its principal argument, Selor maintains that the contractual provisions 
governing is relationship with Top System entail the waiver by Top System of its 
right to rely on copyright with regard to any use of the applications. Selor infers 
from this that it has a right of access to the sources of all the applications provided 
by Top System, which includes the possibility of accessing those sources itself, by 
means of decompilation. 
16 In the alternative, Selor maintains that decompilation was legally permitted for the 
purpose of correcting errors, in accordance with Directive 91/250. According to 
Selor, the design flaws affecting the program designed by Top System (in 
particular, two applications within the TSF program) and the latter’s failure to 
respond to and provide a solution for the problems which it had complained of 
made it impossible to use the program as intended, and that that justified the 
decompilation. Selor also argues that it is entitled to ‘observe, study or test the 
functioning’ of the program ‘in order to determine the ideas and principles’ 
underlying the functionalities of TSF at issue, so that it can circumvent the 
blockages they were causing (Article 5(3) of Directive 91/250). 
Top System 
17 Top System complains that Selor decompiled its ‘TSF’ program without being 
authorised to do so, either under contract or by law. It also states that it would in 
TOP SYSTEM 
 
5 
any event be opposed to such decompilation on the ground that ‘the applications 
are one thing, the TSF Framework is another’. It submits that TSF was not 
developed for Selor and that Selor did not fund TSF, which was developed 
internally by Top System and belongs exclusively to it. 
18 As regards the legal entitlement to decompile, it maintains that decompilation may 
only be carried out in order to ensure the interoperability of programs (Article 6 of 
the directive), not to correct errors (Article 5(1) of the directive), the existence of 
which, moreover, it disputes. Should the cour d’appel (Court of Appeal) consider 
interpreting the legal provision (transposing Article 5 of the directive) as 
permitting the correction of errors, Top System asks that it refer a question to the 
Court of Justice for a preliminary ruling. In the alternative, Top System maintains 
that, if decompilation is justified in such case, it must be carried out under the 
strict conditions laid down in Article 6 of the directive. 
19 As regards the exception referred to in Article 5(3) of the directive, Top System 
claims that the decompilation did not take place solely in a testing environment, 
but also in a development environment, that of Selor’s computer programmers. 
4. Assessment of the referring court 
20 The cour d’appel (Court of Appeal) emphasises that Top System did not deliver 
the entirety of the source code for the Selor applications. 
21 Faced with a failure to perform the contract, Selor should have put Top System on 
notice to send it the source code, rather than go ahead and decompile the object 
code. Since Selor had refrained from putting Top System on notice to provide it 
with the source code to which it was contractually entitled, and since it had 
deliberately placed itself outside the scope of performance of the contract, it was 
up to Selor to demonstrate that it had satisfied the legal conditions for carrying out 
the decompilation. 
22 The cour d’appel (Court of Appeal) briefly states the positions of the parties as 
follows. According to Top System, there are only two situations in which 
decompilation may be carried out, that is to say, where the author has authorised it 
and where it is sought to achieve interoperability (Article 6 of the directive). On 
the other hand, decompilation is not permitted in order to correct errors, contrary 
to what was held in the judgment under appeal. According to Selor, however, the 
correction of errors, by means of decompilation, is permitted by the provision of 
national law (transposing Article 5(1) of the directive), which permits all of the 
acts contemplated by Article 4(b) of the directive to be carried out and thus, in 
addition to translation, adaptation and arrangement, ‘any other alteration of a 
computer program and the reproduction of the results thereof’. 
23 The cour d’appel (Court of Appeal) finds that the exception under Article 5(3) of 
the directive does not apply. That provision merely permits the person having a 
right to use a copy of the computer program to observe, study or test the 
SUMMARY OF THE REQUEST FOR A PRELIMINARY RULING — CASE C-13/20 
 
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functioning of the program in order to determine the ideas and principles which 
underlie any element of the program if he does so while performing any of the 
acts of loading, displaying, running, transmitting or storing the program which he 
is entitled to do. The court considers that the decompilation carried out by Selor 
obviously went beyond that framework. 
24 The question therefore is whether the decompilation of all or part of a computer 
program constitutes one of the acts contemplated by Article 4(a) and (b) of 
Directive 91/250 which a lawful user of a program may carry out for the purposes 
of error correction. 
25 Neither the wording of the directive, nor the existing case-law provides sufficient 
guidance to answer this new question of interpretation of the directive, which is in 
the general interest of the uniform application of EU law. 
5. Questions referred for a preliminary ruling 
26 The cour d’appel (Court of Appeal) refers the following questions to the Court of 
Justice for a preliminary ruling: 
– Is Article 5(1) of Council Directive 91/250/EEC of 14 May 1991 on the legal 
protection of computer programs to be interpreted as permitting the lawful 
purchaser of a computer program to decompile all or part of that program 
where such decompilation is necessary to enable that person to correct errors 
affecting the operation of the program, including where the correction consists 
in disabling a function that is affecting the proper operation of the application 
of which the program forms a part? 
– In the event that that question is answered in the affirmative, must the 
conditions referred to in Article 6, or any other conditions, also be satisfied?