diff --git a/Doc/faq/programming.rst b/Doc/faq/programming.rst
--- a/Doc/faq/programming.rst
+++ b/Doc/faq/programming.rst
@@ -1103,6 +1103,34 @@
    result = [obj.method() for obj in mylist]
 
 
+Why does aTuple[0] += 'item' raise an exception?
+------------------------------------------------
+
+Because '+=' is an assignment operator and tries to
+update the, read-only, tuple.
+
+When the added-to item is a list the update of this list
+will succeed::
+
+    >>> aTuple = ([],)
+    >>> aTuple[0] += [1, 2]
+    Traceback (most recent call last):
+      File "<stdin>", line 1, in <module>
+      TypeError: 'tuple' object does not support item assignment
+    >>> aTuple
+    ([1, 2],)
+
+The list is updated because the '+=' operator is more or
+less equivalent to::
+
+    >>> tmp = aTuple[0]
+    >>> tmp.__iadd__([1,2])
+    >>> aTuple[0] = tmp
+
+The call to *__iadd__* succeeds, but the update of
+*aTuple* fails.
+
+
 Dictionaries
 ============