Yes, you can get paralyzed.
Starting to focus is not considered to be executing the move, and effects based on move order (such as Zoom Lens) will not activate from it.
Source.
I also tested it in game. Whether a Pokemon is inflicted with Paralysis prior to using Focus Punch or during the turn they use it, the user always tightens their focus first, then paralysis will take effect when the user tries to attack.
Hope this helped!
