Editor and accent

Hi,

In the TAB "Text Editors", When i use the "Active editor" in the "Front Editor", the accent of the message is ko.
example : "Test Fred pour corriger les pb d'accent : é è à"

intead of "Test Fred pour corriger les pb d'accent : é è à "

I search in the parameters but i don't thinks it's this.
Can you help me please ?
Thanks a lot

PS : When i use the same editor in a joomla article it's ok.
Fred