The validator change the declared encoding

I think this line is correct :
    <meta charset="ISO-8859-1" /> (I look at W3 school..)

Why did I get this message :
    Using windows-1252 instead of the declared encoding iso-8859-1.

adress : http://amade.pagesperso-orange.fr/chorege/contacter.html

Thank's for your help

Jean CHEVALLIER