From reports at: http://athens.indymedia.org/front.php3?lang=el&article_id=821039
There was an attack with paint bombs, during the demonstration organized by local anarchists to denounce the kidnapping of a companion by cops/state agents. Their companion was taken in the Police Station in Dikeosinis ("justice") avenue, in the city center. The demo was large enough, some 250/300 people attended despite of the aweful weather conditions and marched through the central streets of Heraklion, to return to the point it started from (Liontaria). Apart from the anarchist bloc, there was also a small bloc of around 10 persons from EAAK (left-wing students).
"Zero tolerate against the police"
There are also report that there were some clashes with the policemen, who used tear gas.