diff --git a/src/Symfony/Component/HttpFoundation/Request.php b/src/Symfony/Component/HttpFoundation/Request.php
index a29037279a..85b5a53f4f 100644
--- a/src/Symfony/Component/HttpFoundation/Request.php
+++ b/src/Symfony/Component/HttpFoundation/Request.php
@@ -1367,7 +1367,7 @@ class Request
      *  * _format request parameter
      *  * $default
      *
-     * @param string $default The default format
+     * @param string|null $default The default format
      *
      * @return string The request format
      */
diff --git a/src/Symfony/Component/HttpKernel/Fragment/InlineFragmentRenderer.php b/src/Symfony/Component/HttpKernel/Fragment/InlineFragmentRenderer.php
index 712248578d..13fc335624 100644
--- a/src/Symfony/Component/HttpKernel/Fragment/InlineFragmentRenderer.php
+++ b/src/Symfony/Component/HttpKernel/Fragment/InlineFragmentRenderer.php
@@ -122,6 +122,13 @@ class InlineFragmentRenderer extends RoutableFragmentRenderer
             $subRequest->setSession($session);
         }
 
+        if ($request->get('_format')) {
+            $subRequest->attributes->set('_format', $request->get('_format'));
+        }
+        if ($request->getDefaultLocale() !== $request->getLocale()) {
+            $subRequest->setLocale($request->getLocale());
+        }
+
         return $subRequest;
     }
 
diff --git a/src/Symfony/Component/HttpKernel/Tests/Fragment/InlineFragmentRendererTest.php b/src/Symfony/Component/HttpKernel/Tests/Fragment/InlineFragmentRendererTest.php
index 197a720439..6cd2bf03ca 100644
--- a/src/Symfony/Component/HttpKernel/Tests/Fragment/InlineFragmentRendererTest.php
+++ b/src/Symfony/Component/HttpKernel/Tests/Fragment/InlineFragmentRendererTest.php
@@ -175,6 +175,26 @@ class InlineFragmentRendererTest extends TestCase
         $this->assertEquals('Foo', ob_get_clean());
     }
 
+    public function testLocaleAndFormatAreIsKeptInSubrequest()
+    {
+        $expectedSubRequest = Request::create('/');
+        $expectedSubRequest->attributes->set('_format', 'foo');
+        $expectedSubRequest->setLocale('fr');
+        if (Request::getTrustedHeaderName(Request::HEADER_CLIENT_IP)) {
+            $expectedSubRequest->headers->set('x-forwarded-for', array('127.0.0.1'));
+            $expectedSubRequest->server->set('HTTP_X_FORWARDED_FOR', '127.0.0.1');
+        }
+        $expectedSubRequest->headers->set('forwarded', array('for="127.0.0.1";host="localhost";proto=http'));
+        $expectedSubRequest->server->set('HTTP_FORWARDED', 'for="127.0.0.1";host="localhost";proto=http');
+
+        $strategy = new InlineFragmentRenderer($this->getKernelExpectingRequest($expectedSubRequest));
+
+        $request = Request::create('/');
+        $request->attributes->set('_format', 'foo');
+        $request->setLocale('fr');
+        $strategy->render('/', $request);
+    }
+
     public function testESIHeaderIsKeptInSubrequest()
     {
         $expectedSubRequest = Request::create('/');
diff --git a/src/Symfony/Component/Security/Http/HttpUtils.php b/src/Symfony/Component/Security/Http/HttpUtils.php
index 60498231a6..b0377bb44f 100644
--- a/src/Symfony/Component/Security/Http/HttpUtils.php
+++ b/src/Symfony/Component/Security/Http/HttpUtils.php
@@ -91,6 +91,13 @@ class HttpUtils
             $newRequest->attributes->set(Security::LAST_USERNAME, $request->attributes->get(Security::LAST_USERNAME));
         }
 
+        if ($request->get('_format')) {
+            $newRequest->attributes->set('_format', $request->get('_format'));
+        }
+        if ($request->getDefaultLocale() !== $request->getLocale()) {
+            $newRequest->setLocale($request->getLocale());
+        }
+
         return $newRequest;
     }