Terry: the comment isn't self-contradictory. Instead, the file constitutes a perfectly fine iso-8859-15 byte sequence (albeit a meaningless one: any byte sequence is perfectly fine iso-8559-15, and, in a comment, any characters are allowed by the Python syntax).

AFAICT, the file also follows the wording of PEP 263, as it does not disallow additional text on the encoding line. Therefore, I think tokenize should accept the file.