Poland has fined Russia’s state-owned Gazprom $7.6 billion and five European companies a combined $61 million for allegedly forming an illegal partnership to build the controversial Nord Stream 2 (NS2) pipeline to bring more Russian natural gas to Europe.

Nord Stream Pipeline

Gazprom management told NGI Thursday that the company “fundamentally disagrees” with Wednesday’s decision by Polish anti-monopoly authority, the Office of Competition and Consumer Protection, aka UOKiK, and plans to appeal. The $11.2 billion NS2 pipeline project was not implemented by a joint venture but by a Gazprom subsidiary, “with the attraction of debt financing” provided by the European companies, management said.

“UOKiK’s decision violates the principles of legality, proportionality and fair trial, and the...