Anti-globalisation activists rioted for a third night in Hamburg, with 186 protesters arrested, even after G20 leaders had left the city.
Cars were torched, shops looted, bikes burned in street barricades and windows smashed during the three days of violence and 476 officers were injured.
German police again used water cannon trucks against rioters who attacked them with iron rods and pavement stones.
They detained another 225 people temporarily, apart from the arrests.
Foreign minister Sigmar Gabriel condemned the violence and said a Europe-wide investigative team should search for suspects.
He added: "Germany's reputation is severely affected internationally by the events in Hamburg."
The city's police president Ralf Meyer said he was proud of the 20,000 officers who managed to provide security for the many international leaders and their delegations.
But it was deplorable that so many of the officers were injured and that the violent riots could not be prevented, he said.
The city's interior minister, Andy Grote, said they had not expected this kind of brutality by leftist extremists, adding: "We had to deal – detached from the actual events at the summit – with ruthless acts of violence by criminals."
Hamburg's officials said those who suffered from the destruction would quickly receive financial support from the government.
The overwhelming majority of the tens of thousands who took to the streets protested peacefully against the G20 summit, demanding quicker action against global warming and more help for refugees.
German chancellor Angela Merkel hosted the summit which was held on Friday and Saturday.
