The court issued its ruling even though Poland already amended the law in 2018 to make the retirement age the same for men and women, with some judges choosing to return to work. The court said some of the current provisions remain unclear.
The court rejected Poland's argument that the 2017 law could be seen as positive discrimination in favor of women and said the measure's giving the justice minister the ability to retain certain judges beyond their retirement age could breach judicial independence.
The case was brought by the European Commission, the EU's executive branch, which called it "an important ruling in support of the independence of the judiciary in Poland and beyond, as well as to prevent discrimination on the basis of gender."
Poland's Foreign Ministry noted that the EU court's judgment "concerns a historical condition which does not reflect the current provisions." The Foreign Ministry said the court "should have withdrawn the complaint after the amendment to the act entered into force." It also said Poland remains convinced that the original legislation did not violate judicial independence and should have been allowed to stand.
Supreme Court spokesman Michal Laskowski said that although the criticized legislation is no longer in force, the ruling "sets standards for the future and also for other European countries." Since the Law and Justice party came to power in 2015, Polish government authorities have increasingly taken control of the judicial system, replacing judges and prosecutors forced into retirement with their own picks.
In a latest stunning move, the ruling right-wing party recommended its controversial officials to the Constitutional Tribunal, to increase its control of the top court. Stanislaw Piotrowicz was a communist-era state prosecutor and a key figure in the recent reshaping of the judicial system. He failed to win a second term in parliament.
Former lawmaker Krystyna Pawlowicz has often drawn criticism for her strong views and emotional statements.