I have this char in an xml file:
fumè
I t
You do not need to decode XML for ElementTree to work. XML carries it's own encoding information (defaulting to UTF-8) and ElementTree does the work for you, outputting unicode:
>>> data = '''\
...
...
... fumè
...
...
... '''
>>> x = ElementTree.fromstring(data)
>>> x[0][0].text
u'fum\xe8'
If your data is contained in a file(like) object, just pass the filename or file object directly to the ElementTree.parse() function:
x = ElementTree.parse('file.xml')