On November 20 a nationwide general strike was called in Greece, public and private sector unions joined the call. The demands were various: wage increases, labor rights, increase funding for several social services, repeal ongoing privatizations. Additionally the Communist Party of Greece (Marxist-Leninist) [KKE (m-l)] was present in many cities of the country, issuing local calls and presenting its contingents in the mobilizations, as well as they made a statement:
https://kkeml.gr/20-noemvrh-oloi-sthn-apergia-oloi-sto-dromo-enantia-sthn-eksathliwsh-kai-thn-tromokratia
In this statement the KKE (m-l) joined the demands by the workers as well as presented other demands such as the expel of the NATO and Yankee military bases, the end of the EU policies and the necessity to raise the solidarity for Palestine and to demand its freedom.
Didn't see this reported here.
from the kke page it looks like the demonstrations were massive. Here's a sample from Athens: