diff --git a/sonar-project.properties b/sonar-project.properties
index 7bd2234b9..95ca0669d 100644
--- a/sonar-project.properties
+++ b/sonar-project.properties
@@ -1,2 +1,6 @@
 sonar.projectKey=storytold_gridcraft
 sonar.organization=storytold
+
+# The region table is one record per locale with the same field names and many shared values
+# (month names, formats); that repetition is data, not copy-pasted logic.
+sonar.cpd.exclusions=crates/core/src/region.rs