diff --git a/Doc/library/string.rst b/Doc/library/string.rst
index f2f3ab9eefdd50..5e2f35497cbe86 100644
--- a/Doc/library/string.rst
+++ b/Doc/library/string.rst
@@ -737,10 +737,10 @@ Using the comma or the underscore as a digit group separator::
    '4996_02d2'
    >>> '{:_}'.format(123456789.123456789)
    '123_456_789.12345679'
-   >>> '{:._}'.format(123456789.123456789)
-   '123456789.123_456_79'
-   >>> '{:_._}'.format(123456789.123456789)
-   '123_456_789.123_456_79'
+   >>> '{:.,}'.format(123456789.123456789)
+   '123456789.123,456,79'
+   >>> '{:,._}'.format(123456789.123456789)
+   '123,456,789.123_456_79'
 
 Expressing a percentage::