I'm not sure it's possible to copy a Windows catalog file over to a Mac since, among other things, the files won't even remotely be in the same directory structure. And it's the catalog file that includes all of the Keyword Tags, etc., you've associated with your media.
It's most likely you'll need to rebuild your media catalog.
Thanks for the answer but I do not know if this kind of problem that I imagined, is resolved DEFINITELY buying again Photoshop Elements for Mac (ie spending still € 149!). At least in this case I want the security that the files jpg treated on Windows 8 is copied in full on the Mac Pro.
Otherwise (ie rewrite bonds etc.) Is sufficient the software Photo free on Mac.
Have you tried using the Backup Catalog tool under the File menu to save your catalog to an external drive -- and then using the Restore Catalog tool on your Mac to restore that back to your Mac? If there is a way to transfer your media and your tags to a new computer, across platforms, this is probably it.
It seems impossible to have a clear answer to this simple question whose answer should be on the first page of the site of Adobe:
Adobe Photoshop Premiere Elements 8 for Wiindows and all its contents in photos and movies are downloadable, copyable, readable ..with certainty IN Adobe Photoshop Premiere Elements for Mac Book Pro?
I have not tried it yet because I have not bought Elements for Mac just because I can not find an insurance to my question and not want to throw € 150