ParseError: not well-formed (invalid token) using cElementTree

It seems to complain about \x08 you will need to escape that.

Edit:

Or you can have the parser ignore the errors using recover

from lxml import etree
parser = etree.XMLParser(recover=True)
etree.fromstring(xmlstring, parser=parser)

I was having the same error (with ElementTree). In my case it was because of encodings, and I was able to solve it without having to use an external library. Hope this helps other people finding this question based on the title. (reference)

import xml.etree.ElementTree as ET
parser = ET.XMLParser(encoding="utf-8")
tree = ET.fromstring(xmlstring, parser=parser)

EDIT: Based on comments, this answer might be outdated. But this did work back when it was answered...