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Stéphane Korvers

How to avoid the language barrier when filing a patent application in Belgium?

Is double patenting permissible at the European Patent Office? (G4/19)
How to avoid the language barrier when filing a patent application in Belgium?

Belgium has a complex institutional system in which the use of official languages is sometimes at the heart of public debate. The laws on the use of languages in administrative matters of July 18, 1966 still play an important role in our lives. But what are the legal consequences of these laws for your Belgian patent application?

Filing a Belgian patent application

In order to validly file a patent application in Belgium, three essential elements must be sent to the Belgian Office for Intellectual Priority (OPRI), as listed in Art. XI.17 §1 of the Code of Economic Law (CEL):

– the first is a description that generally corresponds to the body (i.e. text and drawings) of the patent application,

– the second are indications enabling to establish the applicant’s identity and to contact him, and finally

– the third is an explicit or implicit request for the grant of a patent.

The European Patent Convention provides similar provisions (Art. 80 and Rule 40(1) EPC).

The laws on the use of languages in administrative matters of July 18, 1966

As OPRI is a central federal public service, under Art. 41 and 52 §1 of these laws, individuals may file these elements in the official language of their choice (Dutch, French or German), while private companies (or legal person) established in Belgium in a given language region must file these elements in the language or languages recognized as “official” in that region. The so-called “facilities regime” (allowing the use of more than one language in some municipalities in particular situations) does not apply when filing a patent application.

Derogation for the body of the application

Art. XI.17 §3 CEL reiterates the need to comply with these provisions but also provides for a derogation: for the purposes of assigning a filing date, the body of the application may be filed in any language (as it is the case for a European application, according to Art. 14(2) EPC). However, this derogation has two important explicit limitations:

– it applies only for the purpose of assigning a filing date and therefore, it is necessary to regularize the patent application later on, and

– it only applies to the body of the application and not to the other elements of the filing (such as the request).

Minor consequences …

If the body of the application is filed in an ineligible language, the applicant has three months from the filing to provide a translation into an eligible language (Art. 8ter of the Royal Decree of December 2, 1986 on the application, grant and maintenance of patents for invention). If the applicant fails to do so, OPRI invites them to pay a regularization fee within a new period of three months in accordance with Art. XI. 21 §1 CEL and Art. 26 §1 of the said Royal Decree. Failing to do so, the application is then deemed to be withdrawn. If the translation is filed within the time limit, the date of filing of the application, if any, is not affected.

… and major consequences

On the other hand, if the indications on the applicant and/or the request are in an inadmissible language, no filing date is attributed to the application until these elements are regularized (Art. XI.17 §5 CEL). This can have dramatic consequences, especially when the application is a priority application and the applicant discloses the invention shortly after filing with the thought that a filing date has been granted. The only consolation is that, where possible, the OPRI notifies the applicant as soon as possible, in accordance with Art. 8bis §1 of the said Royal Decree and Art. XI.17 §4 CEL, so that it is possible to react quickly and limit the postponement of the application date in time.


Using the wrong filing language can have serious consequences for your Belgian patent application. Fortunately, with your preferred GEVERS patent attorney, you will be well-informed on how to avoid such serious consequences.

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