diff --git a/src/Symfony/Component/HttpFoundation/Request.php b/src/Symfony/Component/HttpFoundation/Request.php
index afab299767..756f6b7f6c 100644
--- a/src/Symfony/Component/HttpFoundation/Request.php
+++ b/src/Symfony/Component/HttpFoundation/Request.php
@@ -466,32 +466,41 @@ class Request
     /**
      * Normalizes a query string.
      *
-     * It builds a normalized query string, where keys/value pairs are alphabetized
-     * and have consistent escaping.
+     * It builds a normalized query string, where keys/value pairs are alphabetized,
+     * have consistent escaping and unneeded delimiters are removed.
      *
      * @param string $qs Query string
      *
-     * @return string|null A normalized query string for the Request
+     * @return string A normalized query string for the Request
      */
-    static public function normalizeQueryString($qs = null)
+    static public function normalizeQueryString($qs)
     {
-        if (!$qs) {
-            return null;
+        if ('' == $qs) {
+            return '';
         }
 
         $parts = array();
         $order = array();
 
-        foreach (explode('&', $qs) as $segment) {
-            if (false === strpos($segment, '=')) {
-                $parts[] = $segment;
-                $order[] = $segment;
-            } else {
-                $tmp = explode('=', rawurldecode($segment), 2);
-                $parts[] = rawurlencode($tmp[0]).'='.rawurlencode($tmp[1]);
-                $order[] = $tmp[0];
+        foreach (explode('&', $qs) as $param) {
+            if ('' === $param || '=' === $param[0]) {
+                // Ignore useless delimiters, e.g. "x=y&".
+                // Also ignore pairs with empty key, even if there was a value, e.g. "=value", as such nameless values cannot be retrieved anyway.
+                // PHP also does not include them when building _GET.
+                continue;
             }
+
+            $keyValuePair = explode('=', $param, 2);
+
+            // GET parameters, that are submitted from a HTML form, encode spaces as "+" by default (as defined in enctype application/x-www-form-urlencoded).
+            // PHP also converts "+" to spaces when filling the global _GET or when using the function parse_str. This is why we use urldecode and then normalize to
+            // RFC 3986 with rawurlencode.
+            $parts[] = isset($keyValuePair[1]) ?
+                rawurlencode(urldecode($keyValuePair[0])).'='.rawurlencode(urldecode($keyValuePair[1])) :
+                rawurlencode(urldecode($keyValuePair[0]));
+            $order[] = urldecode($keyValuePair[0]);
         }
+
         array_multisort($order, SORT_ASC, $parts);
 
         return implode('&', $parts);
@@ -843,7 +852,8 @@ class Request
      */
     public function getQueryString()
     {
-        return static::normalizeQueryString($this->server->get('QUERY_STRING'));
+        $qs = static::normalizeQueryString($this->server->get('QUERY_STRING'));
+        return '' === $qs ? null : $qs;
     }
 
     /**