I picked up this oddity from Russia on eBay. With little to no details from the seller, it piqued my curiosity and I figured it was worth a few bucks to find out more about this strange item.
My suspicions were correct that this cassette was produced during the MF-era, but I was surprised to discover that most of the tracks of this "greatest hits" compilation were simply a direct rip from MCE, with a handful of Moi... Lolita and L'Alizé remixes thrown in at the end... very strange. The cassette itself seems to be a generic tape for consumer dubbing, and bears no unique markings. I can't say for sure if this cassette was legally produced (my best guess is no), but interestingly there is a disclaimer on the inner cover warning that unauthorized copying is prohibited, which I find more than just a little ironic.