Thousands of demonstrators bearing candles marched on the Polish Supreme Court on Sunday in protest against controversial proposed judicial reforms.
"Constitution, Constitution!" they chanted in front of the court building in Warsaw.
Poland's senate backed on Saturday the Supreme Court reforms, despite warnings from the European Union, appeals from Washington and massive street protests against the measures which reinforce political control over the court.
The move still needs to be signed by President Andrzej Duda to become law and on Sunday the marchers urged him to veto the bill.
"We have come especially with a group of 14 people from (the western city) Wroclaw to protest against the taking control of the courts," Karolina Chorej,a 29-year-old doctor, told AFP.
"We want to call on the president to use his veto, even if we don't have too much hope".
Duda is closely allied with Poland's ruling conservative Law and Justice (PiS) party, which has pushed through the legislation.
Another protester, Michal Bialek, a 30-year-old chemist, called it "an historic moment for our country" adding that "we must fight for the freedom of the courts, for democracy".
The protesters, including many more young people than at previous rallies, held candles aloft as passages from the constitution were read out from a stage erected in front of the Supreme Court.
They also waved Polish and EU flags as well as white roses, the symbol of the civil movement against the reforms.
Similar protests were held Sunday in a hundred other Polish towns, according to media close to the opposition.
The ruling right-wing PiS party has defended the reforms, calling them indispensable to combat corruption and streamline the judicial system.
The European Union has warned the Polish government to suspend the controversial court reform effort or risk unprecedented sanctions.
The proposed reforms "would abolish any remaining judicial independence and put the judiciary under full political control of the government," European Commission vice president Frans Timmermans said last week.