diff --git a/pylast/__init__.py b/pylast/__init__.py
index 8005c71..7020eee 100644
--- a/pylast/__init__.py
+++ b/pylast/__init__.py
@@ -1070,7 +1070,7 @@ class _Request(object):
 
         for key in keys:
             if key != "api_sig" and key != "api_key" and key != "sk":
-                cache_key += key + _string(self.params[key])
+                cache_key += key + self.params[key]
 
         return hashlib.sha1(cache_key.encode("utf-8")).hexdigest()
 
diff --git a/tests/request_test.py b/tests/request_test.py
new file mode 100644
index 0000000..fb18091
--- /dev/null
+++ b/tests/request_test.py
@@ -0,0 +1,17 @@
+# -*- coding: utf-8 -*-
+import mock
+import pytest
+
+import pylast
+
+
+def mock_network():
+    return mock.Mock(
+        _get_ws_auth=mock.Mock(return_value=("", "", ""))
+    )
+
+@pytest.mark.parametrize('unicode_artist', [u'\xe9lafdasfdsafdsa', u'éééééééé'])
+def test_get_cache_key(unicode_artist):
+    request = pylast._Request(mock_network(), 'some_method',
+                              params={'artist': unicode_artist})
+    request._get_cache_key()