She beat fellow Pole Natalia Kałucka, the defending champion, in the bronze-medal race, receiving a standing ovation from the crowd.
Overcome with emotion, she briefly covered her face with her hands before embracing her husband and coach, Mateusz Mirosław.
The climber, Olympic champion from the 2024 Paris Games, announced her retirement on her 32nd birthday in February.
Laval was her second competition of the season and her last.
Alongside her Olympic gold, Mirosław has won two European (2019 and 2022) and three world titles (2018-19 and 2025), and held the world record until July.
Sports Minister Jakub Rutnicki thanked her for representing Poland, writing on social media that she had given the country "reasons to be proud that we won't forget."
Mirosław said the European Championships had ended her career "in the best possible way," reflecting on 17 years of competing with "ups and downs, and no regrets."
(ał)
Source: PAP, polskieradio24.pl