Thank you both.
I do not think I need utf8 as my perl is v5.18 (debian jessie).
Hexdump on my code.pl is correct c3 a9.
Hexdump on my out.xml is incorrect and correspond to my cat : c3 83 c2 a9 (é).
Sorry, I do not know how to check if my "command shell is set to interpret output as ISO Latin". But my locale is : LANG=en_US.UTF-8.
I can use "keep-encoded" to make it work (in this case), but I would like to understand...