diff --git a/eZ/Bundle/EzPublishCoreBundle/EventListener/SessionInitByPostListener.php b/eZ/Bundle/EzPublishCoreBundle/EventListener/SessionInitByPostListener.php
index ba9d13101a..5048b939de 100644
--- a/eZ/Bundle/EzPublishCoreBundle/EventListener/SessionInitByPostListener.php
+++ b/eZ/Bundle/EzPublishCoreBundle/EventListener/SessionInitByPostListener.php
@@ -32,7 +32,7 @@ public function onSiteAccessMatch(PostSiteAccessMatchEvent $event)
             $session = $request->getSession();
         }
 
-        if (!$session || $event->getRequestType() !== HttpKernelInterface::MAIN_REQUEST) {
+        if (null === $session || $event->getRequestType() !== HttpKernelInterface::MAIN_REQUEST) {
             return;
         }
 
diff --git a/eZ/Bundle/EzPublishCoreBundle/Tests/EventListener/SessionInitByPostListenerTest.php b/eZ/Bundle/EzPublishCoreBundle/Tests/EventListener/SessionInitByPostListenerTest.php
index 5bb203732c..76e3cbc50c 100644
--- a/eZ/Bundle/EzPublishCoreBundle/Tests/EventListener/SessionInitByPostListenerTest.php
+++ b/eZ/Bundle/EzPublishCoreBundle/Tests/EventListener/SessionInitByPostListenerTest.php
@@ -118,7 +118,7 @@ public function testOnSiteAccessMatchNewSessionName()
         $this->listener->onSiteAccessMatch($event);
     }
 
-    public function testOnSiteAccessMatchNoSession()
+    public function testOnSiteAccessMatchNoSession(): void
     {
         $request = new Request();