What is your goal? A smooth, even painted wall? Then you have to fully skim coat the lime-cement plaster! That is really the case. The workflow is skim coating, sanding, primer, then either fleece and paint or just paint. Or do you want a rough wall texture? Then of course you paint the plaster directly, but here too, first primer, because plasters absorb, and the primer as an acrylate first closes their pores. Only the plaster texture, which you call a cloud, will then be visible. You will have to live with that.