The re module works with codepoints, it doesn't understand canonical equivalence.

For example, it doesn't recognise that "\N{LATIN CAPITAL LETTER E}\N{COMBINING ACUTE ACCENT}" is equivalent to "\N{LATIN CAPITAL LETTER E WITH ACUTE}".

This is true for Python in general, except for identifiers, which are normalised:

>>> "\N{LATIN CAPITAL LETTER E}\N{COMBINING ACUTE ACCENT}"
'É'
>>> É = 0
>>> "\N{LATIN CAPITAL LETTER E WITH ACUTE}"
'É'
>>> É
0

This also means that, say '.' will match only 1 _codepoint_.