Around 14,000 people have paid tribute to eight officials who died when a gunman opened fire at a council meeting in France.
Both President Jacques Chirac and Prime Minister Lionel Jospin attended the ceremony in the Nanterre stadium outside Paris.
Crime policy has become a major element of the spring presidential campaign, in which Mr Chirac and Mr Jospin are the frontrunners.
Eight people were killed and 19 others wounded when a gunman opened fire on March 27 at the close of a council meeting in Nanterre.
The suspect, 33-year-old Richard Durn, had spoken of suicidal thoughts and a wish to kill others.
A day after the rampage, Durn killed himself by jumping from a window of the Paris police headquarters, while two officers were questioning him.
Speaking at the ceremony, the town's mayor, Jacqueline Fraysse, urged authorities to find answers.
"How was Durn authorised to own weapons?" she asked. "How could a man this dangerous, who had clearly stated his intention to commit suicide ... escape surveillance?"