So the Man of Steel Easter Eggs continue to pile up. This one was mentioned before but I don’t believe it was ever confirmed, well until now. In a recent interview with Empire, Director Zack Snyder explained another Batman reference in the final fight:
“When Zod’s tearing the building apart with his heat vision, there’s a Be Calm And Call Batman sign on the wall there, just really small. You might even have to stop the movie to see it but it’s definitely in there. That’s a Double Negative Productions [Easter Egg]. D Neg is the visual effects company here in London that worked on all the Dark Knight movies, and they definitely did that. And [when I saw it], I was like, That’s awesome.”
It’s clear that Warner Bros. is trying to build a united universe where Batman and Superman exist together, something the Dark Knight movies failed to do.