ZombiU 2 is probably a thing, if Amazon France is to be believed.
A listing for ZombiU 2 has been spotted on Amazon.fr. The listing has since been removed, but not before Jeuxvideo grabbed a couple of screens.
Interestingly, rather than a vague December 2015 date, the listing pointed towards a specific day: October 17, 2015. The listing also mentioned Bandai Namco as a publisher, which is very strange since the game was developed and published by Ubisoft.
Namco could simply be the game’s distributor in the region, or could be the new owner of the IP, albeit very unlikely. There is also a mention of New York as a setting for the sequel. The original game was set in London.
Have a look at the screengrabs below.