I'm not great in that field at all, but in Poland private companies existed. At first (after 1945) they hoped to survive until regime will be gone "in a few years". Then the regime tried to kill those one by one. Private owner was an oppressed enemy, fined, bullyragged, threatened.
Small businesses existed the whole time, but it was not an easy life.
Small businesses existed the whole time, but it was not an easy life.
https://dzieje.pl/ksiazki/prywaciarze-biznes-w-peerelu-1945-... (article about a Polish book on that topic).