Far-left and anti-capitalist protesters from across the European Union have congregated in Hamburg in order to protest the Group of 20 meeting during the week.
Several protesters had set up camps in a local park that had been approved as an assembly point, but overnight camping was disallowed, prompting police to clear out the encampments.
Despite being warned by the police not to do so, about 600 people had set up tents in a local park that had been cleared for protest assembly but not for overnight encampment, which forced authorities to intervene, clearing out the encampment and using pepper spray.
So far, one man has been arrested while protesters claim that several people have been injured, although evidence backing that claim is yet to be seen online or anywhere else.
Local authorities, falling in line with the German constitution, had promised that Hamburg would not become an impermeable fort, and that protesters would be able to, presumably, peacefully assemble.
"We do not want to become a fortress. In this city, criticism of the G20 will be given its space, too," the German interior minister, Thomas de Maiziere, said.
Maiziere had warned on Sunday that violent protesters would not be tolerated.
Several thousand police officers have been called in from different parts of the country to support their colleagues in Hamburg, as have thousands more police vehicles, including water cannon police trucks.
Of the approximately 100,000 people expected to show up at the largest protest, police say that about 4,000 in the anarchist and far-left spectrum are willing to engage in violence.
Whether marching peacefully, holding banners, or destroying public and private property, protestors are traditionally only seen on foot, however the sizeable canals of the harbor city were filled with a flotilla of protesters commandeering small motorized boats as well as kayaks by the dozen.
Footage shows one such small rubber boat, with the logo of Greenpeace painted on its side, cruising next to a massive cargo ship and attempting to paint large yellow letters on the ship's port side.
The crew of the small boat had already managed to hang a banner on the cargo ship, apparently depicting the figure of Chancellor Angela Merkel. While attempting to write, presumably, "END CAPITALISM" on the cargo ship, they were stopped by police boats just before they could finish painting the first "A".
The demonstrations were organized by a dozen groups, small and large, including Oxfam, Greenpeace and the German Trade Union Confederation.
Local residents are reportedly not very amused at the fact that the G20, which causes major disruptions to daily life, is taking place in the city and not some remote location. With restriction of access to several areas, kilometers of barbed wire and some 15,000 police officers, life in Hamburg has yet again become quite dysfunctional.