German President Frank-Walter Steinmeier said Thursday he was worried by the growing number of attacks on politicians at work or on the campaign trail.
"We must never get used to violence in the battle of political opinions," Steinmeier said at an event to mark the 75th anniversary of the German constitution.
The basic law, promulgated in 1949, was a response to Germany's experience with political violence during World War II, Steinmeier said.
"No one knew better than the mothers and fathers of the constitution how violence undermines a democracy and tears down its foundations," Steinmeier said.
The constitution was not an end point but a "compass", Steinmeier said, calling on Germans to maintain a "political culture that is compatible with democracy".
The threat of political violence is growing again in Germany, the president said.
"We have received news of physical attacks on elected officials and politically active people almost every day," he said.
"I am deeply concerned about the coarsening of political life in our country."
Police this month arrested a man on suspicion of hitting a former mayor of Berlin in the head during a visit to a public library.
Franziska Giffey, now the Berlin state economy minister and a member of the ruling Social Democratic Party (SPD), was treated in hospital for light injuries.
Giffey's assault came just days after a European parliament member, also from the SPD, was hospitalised after four people attacked him while he was out canvassing.
Senior members of the government have also been confronted by angry mobs in recent months, with Economy Minister Robert Habeck blocked from leaving a ferry by a group of protesters.
Steinmeier also recalled the politically motivated murder of the conservative politician Walter Luebcke by neo-Nazis in 2019.
"His death is a reminder of how hate can turn into violence," Steinmeier said.
This week also saw proceedings open against the alleged ringleaders of a group who are said to have planned to storm the German parliament and overthrow the government.
The group of so-called Reichsbuerger, who deny the legitimacy of the modern German republic, allegedly planned to take MPs hostage and had compiled "lists of enemies" to be eliminated, according to prosecutors.