diff --git a/src/Bundle/ChillMainBundle/Export/Formatter/SpreadSheetFormatter.php b/src/Bundle/ChillMainBundle/Export/Formatter/SpreadSheetFormatter.php
index 4084bfb4f..6b77e5b2b 100644
--- a/src/Bundle/ChillMainBundle/Export/Formatter/SpreadSheetFormatter.php
+++ b/src/Bundle/ChillMainBundle/Export/Formatter/SpreadSheetFormatter.php
@@ -445,6 +445,8 @@ class SpreadSheetFormatter implements FormatterInterface
             $this->initializeCache($key);
         }
 
+        $value = null === $value ? '' : $value;
+
         return call_user_func($this->cacheDisplayableResult[$key], $value);
     }