KARLSRUHE/FRANKFURT (Reuters) - Germany’s Supreme Court on Thursday threw out a case brought by Axel Springer seeking to ban a popular application that blocks online advertising, in a landmark ruling that deals a blow to the publishing industry.

The court found in favor of Adblock Plus adblockplus.org, an app marketed by a firm called Eyeo that has been downloaded more than 100 million times by users around the world seeking protection from unwanted or intrusive online advertising.

“We are excited that Germany’s highest court upheld the right every internet citizen possesses to block unwanted advertising online,” Adblock Plus said after the verdict.

Springer and other media firms - including ProSiebenSat.1 Media, RTL, the Sueddeutsche Zeitung and Spiegel Online - had brought separate cases against Adblock Plus. It was the first to reach the Supreme Court.

The publisher of Bild and Business Insider argued that blocking online ads violated competition law - as did charging companies to be added to a ‘white list’ whose advertising would be allowed through - and had sought compensation.

In its ruling the court in Karlsruhe struck down the case brought by Springer. It found online ad blockers to be legal, and overturned a lower court decision that operating a white list was tantamount to unfair competition.

Springer said it would appeal to the Constitutional Court on the grounds that ad blockers violated press freedom by disrupting online media and their financial viability.

“We are talking about an attack on the heart of the free media,” Springer’s head of media law, Claas-Hendrick Soehring said after the verdict.