A Spanish court on Thursday ordered Facebook owner Meta to pay local media outlets 479 million euros ($552 million) in compensation for "unfair competition" in breach of EU data protection rules.

The potentially landmark decision was centred on European Union law which obliges companies to obtain users' consent to create lucrative personalised advertising from their data.

Spain's main AMI media association filed a lawsuit in 2023 against the US tech giant, which also owns Instagram and WhatsApp, accusing it of creating "unfair competition" by "systematically" breaking the law between May 2018 and July 2023.

A Madrid commercial court, which heard the case last month, ruled in favour of AMI, saying Meta had gained a "significant competitive advantage" in its digital advertising sales by violating the data protection rules.

The "enormous amount of data that Meta possesses" and processes means there must be "rigorous checks", and "competition law plays a fundamental role", the court explained in its ruling.

AMI said in a statement that the decision "marks a turning point in the defence of professional journalism, competitive balance in the digital advertising market and fundamental rights in a democratic society".

"Meta competed unfairly for years, violating the privacy of millions of users and seriously harming media that did follow the law. It is a victory for democracy, accurate information and fair competition," said AMI director general Irene Lanzaco.

Reporters Without Borders (RSF) welcomed a decision that "opens the way for an efficient offensive against the unfair competition of platforms in Europe with regards to news media".

"The economic collapse of the media, exacerbated by the non-regulation of platforms, constitutes one of the main threats to the right to reliable information and press freedom," said Vincent Berthier, head of the tech desk at RSF.

Spain's far-left deputy prime minister Yolanda Diaz also hailed the ruling, saying "the big US tech companies are not above our sovereignty".

"We have to continue making progress on a European technological model that boosts our economy and guarantees labour rights," she wrote on social media platform Bluesky.

- Meta to appeal -

Meta said it would appeal what it called "a baseless claim that lacks any evidence of alleged harm and wilfully ignores how the online advertising industry works".

"Meta complies with all applicable laws, and has provided clear choices, transparent information and given users a range of tools to control their experience on our services," a company spokesperson said in a statement.

Meta representatives told the trial that user data mattered less than algorithms to generate personalised advertising.

AMI had been seeking 551 million euros in compensation. The compensation and a further 60 million euros in interest are to be paid out to 87 media outlets.

Media groups represented by AMI include Prisa, owner of Spain's top-selling daily El Pais; Vocento, which publishes the conservative newspaper ABC; and Unidad Editorial, whose titles include daily El Mundo and sports newspaper Marca.

Spanish radio and television stations have launched a separate lawsuit against Meta for the same reasons, seeking 160 million euros in damages.

Socialist Prime Minister Pedro Sanchez on Wednesday said Spain would investigate Meta for allegedly violating millions of users' privacy, summoning the company to answer before parliament.