Thousands of people rallied in Hamburg on Sunday to protest at next week's G20 summit, where US President Donald Trump is make his maiden appearance at the forum of major economies.
A police spokesman put the turnout at the demonstration -- the first of dozens scheduled in the runup to the summit on Friday and Saturday -- at around 10,000, while the organisers said the figure was far higher.
The protest was "completely peaceful," the police spokesman told AFP.
The gathering outside city hall took place in parallel with protests by canoeists on the nearby river Alster, while in the port of Hamburg, Greenpeace staged a climate demonstration near a ship laden with coal.
The Group of 20 (G20) comprises leaders of the world's major industrialised and emerging economies.
Hamburg, where summit host Chancellor Angela Merkel was born, is a bustling city that is also an anti-establishment bastion.
Around 30 protests have been scheduled ahead of the summit, and the organisers are hoping for a total turnout of more than 100,000 people.
Hamburg is a citadel of leftwing radicals, and the authorities say they are bracing for possible clashes and property damage.
Interior Minister Thomas de Maiziere, in the Sunday edition of the daily Bild, warned that any violence "should be nipped in the bud".
"Freedom of assembly is only valid for peaceful demonstrations," he said.