Demonstrators threw paint bombs at the European Central Bank and attacked emergency vehicles on Saturday (31 March) in violence which escalated after police tried to arrest several protesters in the heart of Germany's financial capital.
Battles stretched through the night and one officer was taken to intensive care after being singled out by a handful of demonstrators. Officers who went to his aid were met with massive violence, police said.
Saturday's clashes mark one of the first significant outbreaks of violence in Germany connected to recent anti-capitalist demonstrations inspired by the 'Occupy Wall Street' movement.
Police said they arrested 465 people during the "anti-capitalist day" march.
A spokesman for the organisers, anti-capitalist alliance M31, said a group of around 200 protesters broke off the 6,000 strong demonstration and headed to the city centre.
"Frankfurt police intervened during the final part of the march, so we called off the protests. We are not responsible for what happened after that," the spokesman said in a telephone interview on Sunday. Police put the size of the march at 4,000 people.
Making a stand against austerity measures
M31 said the demonstration was shadowed by similar events elsewhere in Europe.
"In Frankfurt, we sent a clear signal against current German and European politics of crisis regulation," M31 said in a statement. "Because of a few broken windows, the police brutally attacked our demonstration, injured dozens and arrested 200 demonstrators."
The group says it is making a stand against European governments' austerity measures and labour reforms.
Police used batons and pepper spray as they tried to arrest protesters and M31 said several people were injured as a result. Police said they did not know how many demonstrators were injured.
The protest march had been on its way to the site of a new ECB building when police intervened. The Bank declined to comment on the attack on its headquarters.