In Białowieża, one of Europe's largest primeval forests, it's claimed too many trees are being cut down.
An EU adviser says Poland's decision to increase wood harvesting has broken European Union law, backing the European Commission against the Polish government.
The European Court of Justice told Warsaw last year it would be fined a €100,000 per day if they did not stop large-scale logging.
The Polish Government has previously said cutting down trees is necessary to make paths safe for hikers and protect existing trees from bark beetle infestation.
But, in some parts of Białowieża forest, EU logging quotas to 2021 have already been reached.
According to official forestry data, an expanded quota in one part of the forest, declared illegal by the European Commission, has been more than half filled despite an injunction,
Poland's environment minister says the country will comply with the final ruling of the EU's top court, which will be made in the coming months. While judges are not obliged to follow the adviser's recommendation, they do so in most cases
Białowieża Forest is a UNESCO World Heitage site and home to the continent's largest herd of European bison as well as unique birds and insects.
The European Commission said on Tuesday it was "taking note" of the ECJ opinion on Białowieża, but would wait for the final ruling before making any further comments.
A spokesperson for the executive also said the Commission was still analysing whether Poland was violating the court's interim injunction issued last year, which ordered the country to stop logging immediately.