Law and the Multiverse examines how superhero (and villain) activities and powers would work legally. It looks at issues like anti-mutant discrimination, whether Iron Man would run afoul of the FAA when he flies in his suit (vs. a hero who can fly without one), the legal ethics of sentencing an immortal villain to life without parole, and so on. I recommend checking it out.
I think it falls a bit short, though, in its strict focus on applying the laws of our world to fictitious ones. Marvel’s Civil War, for example, is predicated on the idea that Marvel’s US legal system has adapted its laws to account for superpowered individuals. It’s likely that laws have been adjusted to allow for, say, evidence obtained by Batman to be presented in court. Otherwise either every criminal could demand to be set free because the chain was tainted, or conversely dirty cops could constantly lose evidence (or plant it) and claim a vigilante had messed with the scene.