Don't believe everything that's leaked by prescient French retailers. Though Amazon France has a good record for revealing release dates, French supermarket E.Leclerc seems to have missed the mark with its posting for a Witcher 3: Wild Hunt Enhanced Edition dated February 5, as spotted by NeoGAF user Renae. Further research by Coreda using the listing's EAN barcode uncovered a Belgian site with the same entry. According to CD Projekt's Pawel Bruza, however, it's collective madness.
"There's no Enhanced Edition of The Witcher 3: Wild Hunt that we are aware of," Burza said on the CD Projekt forums, "this is some kind of error that we will look into."
It could be a brazen cover-up of course, but that doesn't make sense to me. For one thing, we're still due Wild Hunt's biggest expansion, Blood and Wine—why release a second version before the first is complete? For another, CDPR have been enhancing their hearts out in patches which brought the same sort of interface and balance changes boasted by the Enhanced Editions of The Witcher 1 and 2.
Burza doesn't deny the possibility of an Enhanced Edition in future, but I'd expect it to take the form of a complete 'game of the year'-type deal.