>>> s = u'abc'
>>> type(s)
<type 'unicode'>
>>> print 'unicode - %s' % (s,)
unicode - abc

Python 2.7.3
In [1]: '%c' % 123
Out[1]: '{'
In [2]: u'%c' % 123
Out[2]: u'{'
In [3]: u'%c' % 0x439
Out[3]: u'\u0439'
In [4]: print u'%c' % 0x439
й
In [5]: '%c' % 0x439
---------------------------------------------------------------------------
OverflowError                             Traceback (most recent call last)
----> 1 '%c' % 0x439
OverflowError: unsigned byte integer is greater than maximum

Python 3.2.2
>>> '%c' % 0x0439
'й'
>>> '%c' % 123
'{'
>>>