Long-serving mayor Paweł Adamowicz, 53, died on January 14 last year from severe wounds inflicted by a knife-wielding attacker during a high-profile charity event in Gdańsk a day earlier.
He underwent a five-hour operation but doctors were unable to save him.
Adamowicz had been the city's mayor for more than 20 years.
On Friday evening, a plaque commemorating Adamowicz was unveiled in downtown Gdańsk at the site where he was stabbed.
(pk)