I doubt it myself but PSG have some economic incentive to sell - they owe Cavani 73m euro in wages over the next four years and he's a backup striker/out of position 'winger' for the foreseeable future given Ibra's form. They're in trouble with FFP (and we'll see what the consequences are on Thursday). If Cavani wants out, I could see him not being worth the trouble. PSG's purchase price of 63m euro is only £51.7m, I think that's within our range given the Ozil transfer.
If PSG want to get out of FFP trouble and Cavani is willing to take a pay cut to be the main man somewhere, it's possible. Unlikely, but there's no sure thing when you're looking to sign players of this caliber.
Madrid are going to be looking for star power if they sign a striker IMO. Suarez is also a (marginally) better fit for their frontline with his passing ability. They can't buy a pure #9 like Cavani to play with Ronaldo and Bale, would be the height of stupidity.