Around 30,000 protesters took to the streets during May Day rallies in Berlin on Saturday, police said, adding nearly 100 officers were injured when some of the demonstrations turned violent.
Police made around 354 arrests during the demonstrations, which they said were for physical assaults and trespassing.
"The violent riots that occurred is something that I very much regret," Berlin's head of police Barbara Slowik told local broadcaster rbb24.
Some of the injuries occurred after some demonstrators threw fireworks, bottles and rocks during protests over social inequality. About 5,600 police were deployed, and some responded with pepper spray.
The demonstrations were the second May Day protests since the start of the coronavirus pandemic. Turnout was much higher than last year, even though social distancing requirements remain in place.
Protests hit other European capitals too, most notably Paris, where police made 46 arrests as garbage bins were set on fire and the windows of a bank branch were smashed.
In Berlin, police used water cannon to extinguish fires as protesters set ablaze waste bins, barricades and cars.
Demonstrations also took place in several other German cities, including Hamburg and Leipzig, despite Europe's largest economy grappling with a third wave of the pandemic.
On Sunday, data from the Robert Koch Institute (RKI) for infectious diseases showed that the number of confirmed coronavirus cases in Germany increased by 16,290 to 3,416,822.
(Writing by Christoph Steitz; Editing by Cynthia Osterman and Alex Richardson)
