Short answer
Paint flakes because moisture contained in the wall evaporates toward the surface and puts pressure on the coating. Two causes are possible: rising damp by capillary action or water damage.
What the paint reveals
Blisters, paint cracks, peeling patches, or recurring marks may indicate that the substrate is not sound or not dry enough.
The mistake to avoid
Repainting without treating or drying the cause may quickly bring back blisters and marks. The right process starts with identifying the issue.
Do the marks keep coming back despite cleaning?
That is often a sign that the cause needs analysing, not just the surface.
Preparing the request
Describe the height of the problem, the room concerned, recent works, and the age of the building. Photos help guide the next step.
Frequently asked questions
Is anti-moisture paint enough?
It may hide the issue temporarily, but it does not replace analysis of the cause of the moisture.