Removing paint from house 1900

How do I remove the old paint from the plaster? Or would it be enough to just remove the flaking parts? Or the whole thing?

High-pressure cleaner. What sticks, can stay.

Is the plaster underneath still intact? At least at the bottom left, it doesn't look so good anymore. Before you apply new paint, I would check if the plaster needs to be renewed or repaired. A pressure washer is a good thing. We also used a wire brush on our basement plinth.

The loose plaster will also come off.

Hollow plaster does not fly off from the high-pressure cleaner, I was able to confirm that myself with us. The plaster in the picture is probably not something you should just paint over, but to each their own.

If nothing is done against the rising moisture, the new paint will look the same again after a short time.

The recognizable attempt at repair of the constantly peeling base by simply applying an extremely thick layer of (estimated) restoration plaster only made things worse, because the moisture now rises behind it and causes the paint above the base to peel off. So: chisel off the base, dry it out, then plaster everything. Ideally, leave the lowest strip from the base down to the masonry exposed, so everything there can always dry out and nothing else will fall off the rest of the wall.