German President Frank-Walter Steinmeier commemorated the death of police officer Rouven Laur at a ceremony in the western city of Mannheim on Friday.
Laur died in an attack at Mannheim's market square a week ago.
Steinmeier, state premier Winfried Kretschmann and state interior minister Thomas Strobl all paused for a minute's silence at 11:34 am (0934 GMT).
Laur died on Sunday, days after he was injured as he sought to intervene when a man attacked several people during a rally by the anti-Islam movement Pax Europa in Mannheim.
Steinmeier laid a floral tribute at the scene as many gathered on the square to mourn the death of the policeman, aged 29.
The 25-year-old Afghan also injured five participants at the rally on May 31.