Google could face a renewed €1.5 billion (A$2.44 billion) antitrust penalty after a senior European court adviser challenged a ruling that overturned the fine imposed on the technology giant over its online advertising practices.

Advocate General Juliane Kokott has recommended that the Court of Justice of the European Union overturn a September 2024 judgment that cleared Google and parent company Alphabet of the penalty.

The case centres on Google’s AdSense for Search service, which allows third-party websites to display advertisements alongside search results and share advertising revenue with Google.

European regulators accused the company of using restrictive contracts between 2006 and 2016 to prevent competing advertising providers from gaining access to publishers.

Under earlier agreements, publishers were prohibited from displaying advertisements supplied by Google’s competitors.

Revised contracts introduced in 2009 required websites to reserve prominent advertising positions for Google and obtain its approval before changing how rival advertisements appeared.

The European Commission imposed the fine in March 2019, arguing that the restrictions unfairly strengthened Google’s dominance in online search advertising.

However, the EU’s General Court overturned the penalty in 2024, ruling that regulators had failed to adequately consider the duration of individual contracts and whether publishers could terminate agreements or switch providers.

Kokott has now questioned that decision, arguing that the lower court placed excessive emphasis on individual contract terms rather than assessing their combined impact on competition.

She said repeated contract renewals and termination rights that publishers rarely exercised could still contribute to anticompetitive behaviour.

Competition lawyer Vuk Leković said the opinion could have wider implications for dominant technology companies, warning that short-term contracts and termination clauses would not necessarily protect businesses from regulatory action.

Google has consistently rejected allegations that its agreements restricted competition, maintaining that rival advertising providers could compete for publishers when contracts expired.

The company argues that competitors failed to win business because their services were less effective.

A Google spokesperson defended the original court decision, saying European regulators had not demonstrated that its contracts harmed competition.

The European Commission declined to comment.

The dispute comes amid continuing European scrutiny of major technology companies, including Google’s multibillion-euro Android antitrust case and Meta’s ongoing challenge to a €797.72 million penalty involving Facebook Marketplace.

Kokott’s opinion is nonbinding, meaning the EU’s highest court is not required to follow her recommendation.

Even if judges overturn Google’s earlier victory, the original fine would not automatically be reinstated.

Instead, the case would return to the General Court for further examination, including Google’s objections to the penalty.

Any reinstated fine would also need to be reduced because some of the European Commission’s original findings relating to 2016 are no longer subject to appeal.

The eventual ruling could establish an important precedent for how European regulators assess restrictive commercial agreements used by dominant technology companies.