diff --git a/content_plugins/admin.py b/content_plugins/admin.py
index 7195b7b..a096cfb 100644
--- a/content_plugins/admin.py
+++ b/content_plugins/admin.py
@@ -12,6 +12,12 @@ from content_editor.admin import ContentEditorInline
 class ContentInlineBase(ContentEditorInline):
     """
     Empty definition for later use.
+
+    Subclass who override the fields attribute must includes
+    the 'region' and 'ordering' fields:
+
+    class AdminInline(ContentInlineBase):
+        fields = ['region', 'ordering', ... more fields ...]
     """