diff --git a/Doc/library/configparser.rst b/Doc/library/configparser.rst
index a7f75fd6e84..bb282428c5f 100644
--- a/Doc/library/configparser.rst
+++ b/Doc/library/configparser.rst
@@ -935,8 +935,10 @@ ConfigParser Objects
 
    When *default_section* is given, it specifies the name for the special
    section holding default values for other sections and interpolation purposes
-   (normally named ``"DEFAULT"``).  This value can be retrieved and changed on
-   runtime using the ``default_section`` instance attribute.
+   (normally named ``"DEFAULT"``).  This value can be retrieved and changed at
+   runtime using the ``default_section`` instance attribute. This won't
+   re-evaluate an already parsed config file, but will be used when writing
+   parsed settings to a new config file.
 
    Interpolation behaviour may be customized by providing a custom handler
    through the *interpolation* argument. ``None`` can be used to turn off