diff --git a/src/Bundle/ChillPersonBundle/Actions/Upsert/Handler/PersonUpsertHandler.php b/src/Bundle/ChillPersonBundle/Actions/Upsert/Handler/PersonUpsertHandler.php
index d073e7ca9..5d938e1d2 100644
--- a/src/Bundle/ChillPersonBundle/Actions/Upsert/Handler/PersonUpsertHandler.php
+++ b/src/Bundle/ChillPersonBundle/Actions/Upsert/Handler/PersonUpsertHandler.php
@@ -44,7 +44,7 @@ readonly class PersonUpsertHandler
     {
         // 1. Retrieve definition
         $definition = $this->personIdentifierDefinitionRepository->find($message->personIdentifierDefinitionId);
-        if (!$definition) {
+        if (null === $definition) {
             throw new \RuntimeException('PersonIdentifierDefinition not found for id '.$message->personIdentifierDefinitionId);
         }