Taken from Bleedingcool.com:
Plenty of us noticed that the title seems to strip the film of any likeness to the Man of Steel sequel it had once been purported to be, and Smith says that’s no accident, as Warner Bros are really doing Justice League (duh), and this is just the first of several JL-centric films that will tell “one massive story”:
But look, they’re obviously beginning something, and there’s a stretch of these flick. And so this is the beginning of the Justice League, as we all suspected as they were announcing that cast. We were like, ‘This is the beginning of a Justice League movie.’ From what I understand now, it’s no longer like, ‘This is Superman 2.’ They’re not doing these things. They’re doing like, ‘Here’s Man of Steel. Here’s Batman/Superman: Dawn of Justice.’ The next one is not like a sequel to one of the characters. They’re just going to keep building their universe for about five or six movies.. But all of them… it’s supposed to tell one massive story, which is all Justice League oriented.