Terminal output to file > NOT valid UTF-8 encoding

Redirecting text with special characters and accents from the Terminal to a file produces an invalid UTF-8 encoding and i have a problem when attempting to display these characters with a text editor.

for example:

$ echo ééé > test

$ cat test

I am using Manjaro xfce 0.8.11 / x86_64 and my locale.conf is LANG=fr_FR.UTF-8

When displaying other locales, such as Arabic or Chinese characters, I don't have this issue!

A similar issue from a user on the manjaro.fr forums : Problème encodage UTF-8 NON valide

any idea ?