The domain fix patch is prepared to be deployed via Wyse Device Manager. If you do not use this nice tool, then you can simply copy the windows folder from the package to the client. Open the .rsp file with notepad to verify what the script would do. Do the same manualy. Very easy one but remember to disable the write filter first.
To get all dialogs beeing shown in french simply open the Control Panel – Regional Setting and click on the last tab. There is a checkbox to enable these settings for the current and default user. This is doing the trick for you.