Yes there is! Export your PAF file to a GEDCOM. (The "export to GEDCOM" is probably under PAF's File menu.) Copy the resulting GEDCOM file to a CD or to a memory stick. Insert the CD or memory stick into your Mac.
Create a new file.
One of the options when creating a new file in Reunion is "Import from GEDCOM". Select this.
Look for the GEDCOM file on your CD or memory stick. Double click.
It may take several minutes, but Reunion will take the data in the GEDCOM and convert it into its own format.
(who also converted from Windows to Mac not that long ago)