This happened before Greece was cornered between a hard place and a rock by the international bankster mafia, so maybe you don't remember, but such a day as yesterday in 2008, police murdered revolutionary activist Alexis Grigorpoulos, triggering the worst civil clashes in decades.
Four years later, in spite of all what Greece has gone through, the People has not forgotten and have gone out to the streets to challenge the Nazi policemen (who vote massively for Golden Dawn and collaborate with them in their racist attacks).
At least in the popular Athenian neighborhood of Exarcheia and also in the Western town of Agrinio, activists have clashed with the police in rememberance of this state murder and all what represents for a Greece divided between the coward lackeys of the international banksters and one of the strongest revolutionary movements of all Europe and the World.
In the small town of Agrinio, this time people, mostly students, did not wait until police intervened but directly attacked them with Molotov cocktails and stones, to which police responded with tear gas and in one case at least threatening with the use of live fire. The march was so well organized and had such strong support by bystanders that nobody has been arrested so far.
In Athens instead the arrest count is of 78, nine being charged. The hardened citizens of Exarcheia, where the murder took place, set up barricades, which the police could not storm in spite of many attempts.
Update: Contra Info has also a video of the clashes in Exarchia → LINK.
Update: Contra Info reports that one victim of police violence lost his spleen → LINK.