I would separate them based on the difference in melting point. Paraffin wax has a melting point range between 125 and 160 degrees C depending on the source of the wax. I could not find a melting point for tar mostly because it would depend on how the tar was made and what specific chemicals and percentages it contained. But I would think that tar would generally have a higher melting point than paraffin wax. So you could take the mixture and heat it slowly until the paraffin started melting. You could then tilt the vessel and pour off the paraffin or you could heat it up in some kind of sieve where the liquid paraffin would drip through the sieve into a container below. The tar would be soft at that temperature but it would probably not melt and remain as a solid.