McAfee product installs accordingly to the language of your operating system. No matter you purchase from which country site, the installer detects your OS language and installs accordingly. Moreover, please visit our official site : http://home.mcafee.com/Default.aspx?culture=FR-FR to make purchases .
But can I have one OS language and chouse other language for Mcaffe?
No. The software adopts the language of your system. It used to be like that but not any more.