diff --git a/src/Symfony/Component/Routing/Generator/UrlGenerator.php b/src/Symfony/Component/Routing/Generator/UrlGenerator.php
index a67b1f41c64e..d9fc9507ee33 100644
--- a/src/Symfony/Component/Routing/Generator/UrlGenerator.php
+++ b/src/Symfony/Component/Routing/Generator/UrlGenerator.php
@@ -98,7 +98,8 @@ protected function doGenerate($variables, $defaults, $requirements, $tokens, $pa
                         throw new \InvalidArgumentException(sprintf('Parameter "%s" for route "%s" must match "%s" ("%s" given).', $token[3], $name, $requirements[$token[3]], $tparams[$token[3]]));
                     }
 
-                    $url = $token[1].urlencode($tparams[$token[3]]).$url;
+                    // %2F is not valid in a URL, so we double encode it
+                    $url = $token[1].str_replace('%2F', '%252F', urlencode($tparams[$token[3]])).$url;
                     $optional = false;
                 }
             } elseif ('text' === $token[0]) {
diff --git a/src/Symfony/Component/Routing/Matcher/UrlMatcher.php b/src/Symfony/Component/Routing/Matcher/UrlMatcher.php
index 10eb8f9a0c7c..929b4af6c22e 100644
--- a/src/Symfony/Component/Routing/Matcher/UrlMatcher.php
+++ b/src/Symfony/Component/Routing/Matcher/UrlMatcher.php
@@ -91,7 +91,8 @@ protected function mergeDefaults($params, $defaults)
         $parameters = array_merge($this->defaults, $defaults);
         foreach ($params as $key => $value) {
             if (!is_int($key)) {
-                $parameters[$key] = urldecode($value);
+                // / are double-encoded as %2F is not valid in a URL (see UrlGenerator)
+                $parameters[$key] = str_replace('%2F', '/', urldecode($value));
             }
         }