diff --git a/src/ShopCertification.php b/src/ShopCertification.php
index 2f9510a..3b05135 100644
--- a/src/ShopCertification.php
+++ b/src/ShopCertification.php
@@ -127,7 +127,7 @@ public function addProductItemId($productItemId)
 
         if (array_search($productItemId, $this->productItemIds) !== false) {
             throw new DuplicateProductItemIdException(
-                'The productItemId "%s" was already added. Please check the implementation.'
+                sprintf('The productItemId "%s" was already added. Please check the implementation.', $productItemId)
             );
         }