A board announcing Spanish language lessons is seen on March 17, 2016 in Benalmadena, Spain | David Ramos/Getty Images EU institutions can’t discriminate based on language, court rules European Court of Justice finds fault with recruitment process for Parliament drivers.

European institutions cannot require job applicants to speak specific languages such as English or French unless they provide sufficient justification, the European Court of Justice (ECJ) ruled on Tuesday.

The decision effectively confirms a 2016 ruling by the EU's General Court, which stated that it is — in principle — unlawful for EU institutions to treat applicants differently based on their language skills when hiring staff.

In Tuesday's judgement, the ECJ found in favor of Spain, which brought a discrimination case before the court, and rejected a request by the European Commission to annul the General Court's 2016 ruling.

Spain had taken exception to a call for applications launched by the European Parliament when it was seeking to hire drivers in 2016. The job description required the drivers to have "satisfactory knowledge" of either English, French or German in addition to speaking one of the EU's 24 official languages.

Application forms for the position were available only in these three languages, leading the ECJ to conclude that the hiring process resulted in "a difference based on language, which is in principle prohibited."

The ECJ noted that there is no general ban on requiring applicants to speak certain languages. Different treatment based on language skills may be allowed if justified, the court said, for instance if the duties of the position require specific language skills.

But in the case of the drivers, the ECJ found that the European Parliament had not provided sufficient justification.

"The Parliament did not establish how each of those languages would be particularly useful for the performance of the duties in question and why that choice could not include other official languages which may be relevant to those duties," the court's ruling said.

The Parliament had defended its language requirement with the argument that English, French and German are the most widely used languages in the institution, but the ECJ decided that "it cannot be affirmed that those three languages are, necessarily, the most useful languages for all duties in that institution."

The ECJ therefore annulled the call for applications and declared the database established under the call as void.

At the same time, the ECJ rejected a request by the European Commission to annul a 2016 General Court ruling on a similar case, affirming that "a candidate's highest standards of ability, efficiency and integrity are independent of language knowledge."