The board of the opera sued the news portal over an opinion piece published in summer 2014.
The article, titled "How the Latvian National Opera Became a Public House in Putin's Court", criticizes the board of the opera about renting its space for a private party held by the Russian artist Igor Krutoy whom the piece called "loyal to and trusted by the Kremlin".
It contains a number of claims related to the opera's board members Zigmars Liepiņš, Daina Markova un Inese Eglīte.
Toms Ostrovskis, the deputy editor-in-chief of Tvnet, told Latvian Radio that the portal will appeal the sentence.
He argued that the piece had been clearly named an opinion piece as opposed to being presented as news. He also argued that the content of the publication still stands.
"I am sure that the Latvian National Opera agreement with the New Wave organizer Mr Krutoy was not acceptable neither yesterday nor today. [..] So we're going to appeal this ruling. We're thinking to go all the way, so to speak," said Ostrovskis.
While Zigmars Liepiņš, the head of the opera, posted the news on Facebook and added that "The mill of God grinds slowly but surely".
While Latvia's main journalism body, the Latvian Journalists' Association (LŽA), on Friday issued a statement calling the ruling "legally absurd" and "seriously threatening freedom of speech".
The association claimed the €129,000 fine to be disproportional.
"Similar biting, satirical pieces have been a part of Latvian journalism for years. Editorial comments, columns, caricatures, and newspaper feuilletons have served to spark discussion over publicly important topics and [the journalism genres'] right to exist is guaranteed by the Constitution," reads the announcement.
The association also said that the court's argument on the compensation being so steep so that it "would stop the accused and other persons from similar inflictions of injury in the future" didn't pass scrutiny as it opposes the constitutionally-guaranteed right to freedom of speech and experssion.
The journalist body also said that the court claimed the article was not a news story, an opinion piece or a literary text, without however specifying what the article was exactly. Thus, the association goes on, the court has made interpretation too wide about every published text and blurred legal definitions concerning such texts.
"The LŽA thinks that the verdict undermines the judicial system in Latvia. The verdict is absurd and threatens freedom of speech and expression, which is one of the pillars of the country," concludes the association.