France's antitrust watchdog on Monday fined Google 220 million euros ($267 million) after a probe found it had abused its market power to favor its own services for placing online ads at the expense of rivals.

The penalty is part of a settlement reached after three media groups – News Corp, French daily Le Figaro and Belgium's Groupe Rossel – accused Google of effectively having a monopoly over ad sales for their websites and apps.

The French regulator's decision is an attempt to rebalance the power struggle over online ads in favor of publishers, which held sway in the business in the pre-Internet era but lost considerable ground with the rise of Google and Facebook.

The settlement with Google shows the firm is ready to bend to antitrust pressure and make operational changes to some of its most popular ad business tools, whose success relies on the trove of data it has amassed over the years.

The competition authority determined that Google gave preferential treatment to its own ad inventory auction service AdX and to Doubleclick Ad Exchange, its real-time platform for letting clients choose and buy ads.

Google did not contest the findings, and the regulator said the company has committed to operational changes, including improved interoperability with third-party ad placement providers.

"We are going to test and develop these changes in the coming months before deploying them more broadly, including some on a global scale," Maria Gomri, legal director at Google France, said in a statement.

The fine represents just a tiny fraction of the $55.3 billion in revenue booked by Google in the first quarter of this year alone, mainly from online ad sales.

The ruling comes as American technology firms are drawing closer scrutiny from European authorities, which are giving themselves new resources to better understand the complex workings of fast-evolving markets.

Last week, Germany's competition regulator said it was expanding an antitrust investigation into Google and its parent company Alphabet to include Google News Showcase, a service aimed at increasing revenue for media publishers.

Facebook also found itself targeted last week by parallel competition inquiries from the European Union and Britain, into whether the social media giant uses data from advertisers to unfairly dominate the online classifieds market.

(With input from Reuters, AFP)