Marx's idea was the "dictatorship of the proletariat" and its evolution into a "classless society", without discussing the details of the governance, though he did quote the example of the Paris Commune (the following quote is from Wikipedia):

The Commune was formed of the municipal councilors, chosen by universal suffrage in the various wards of the town, responsible, and revocable at short terms. The majority of its members were naturally workers, or acknowledged representatives of the working class. The Commune was to be a working, not a parliamentary body, executive, and legislative at the same time. This form of popular government, featuring revocable election of councilors and maximal public participation in governance, resembles contemporary direct democracy.