diff --git a/cinderclient/api_versions.py b/cinderclient/api_versions.py
index a74f3af24..6644684b6 100644
--- a/cinderclient/api_versions.py
+++ b/cinderclient/api_versions.py
@@ -228,7 +228,7 @@ def get_api_version(version_string):
     version_string = str(version_string)
     if version_string in DEPRECATED_VERSIONS:
         LOG.warning("Version %(deprecated_version)s is deprecated, use "
-                    "alternative version %(alternative)s instead." %
+                    "alternative version %(alternative)s instead.",
                    {"deprecated_version": version_string,
                     "alternative": DEPRECATED_VERSIONS[version_string]})
     if strutils.is_int_like(version_string):