Thanks sebboh !
It fix the error. I've already read the thread on the mailing list but didn't see that the package should be install as root !
I have now other problems with UTF-8 :
* I can't open file containing non ASCII characters with libreoffice
* I can't type non ASCII characters in zsh
Don't know if this is related to this bug or not. Will try to reboot to see if it changes something.
Anyway, thanks for your help !