diff --git a/app/src/frontend/building/data-components/planning-data-entry.tsx b/app/src/frontend/building/data-components/planning-data-entry.tsx
index 91ba49d5..b41ae360 100644
--- a/app/src/frontend/building/data-components/planning-data-entry.tsx
+++ b/app/src/frontend/building/data-components/planning-data-entry.tsx
@@ -99,6 +99,9 @@ const PlanningDataOfficialDataEntry: React.FC<PlanningDataOfficialDataEntryProps
     }
   }
   return <>
+        <InfoBox type='success'>
+          To see planning applications visualised for different periods click on the dropdown on the map key.
+        </InfoBox>
         <InfoBox type='success'>
           {/* TODO: data[0] is problematic here... Compute it from listed elements and show all distinct variants? Error if they are not distinct? Hardcode it? */}
           <div>