diff --git a/src/Gaufrette/FilesystemMap.php b/src/Gaufrette/FilesystemMap.php
index 384e69721..96deae392 100644
--- a/src/Gaufrette/FilesystemMap.php
+++ b/src/Gaufrette/FilesystemMap.php
@@ -26,12 +26,12 @@ public function all()
      * Register the given filesystem for the specified domain.
      *
      * @param string     $domain
-     * @param Filesystem $filesystem
+     * @param FilesystemInterface $filesystem
      *
-     * @throws InvalidArgumentException when the specified domain contains
+     * @throws \InvalidArgumentException when the specified domain contains
      *                                  forbidden characters
      */
-    public function set($domain, Filesystem $filesystem)
+    public function set($domain, FilesystemInterface $filesystem)
     {
         if (!preg_match('/^[-_a-zA-Z0-9]+$/', $domain)) {
             throw new \InvalidArgumentException(sprintf(
@@ -61,9 +61,9 @@ public function has($domain)
      *
      * @param string $domain
      *
-     * @return Filesystem
+     * @return FilesystemInterface
      *
-     * @throw  InvalidArgumentException when there is no filesystem registered
+     * @throw  \InvalidArgumentException when there is no filesystem registered
      *                                  for the specified domain
      */
     public function get($domain)