Only presenting a negative Covid-19 test does not exempt the travelers from crossing external and internal EU/Schengen borders from the quarantine obligation.
External EU/Schengen border
Only the following groups of people are allowed to enter the external EU/Schengen border to enter Poland without quarantine:
People who have received one of the vaccines that are recognized in the EU
People who have fully recovered from Covid-19
Certain categories of people (e.g., diplomats, soldiers, aircraft crews, etc.)
Mandatory 10-day quarantine applies for travel from non-Schengen countries or non-member states of the EU.