Unless you're trying to make a movie on the sly, there's no way to get around this. If you want to use public spaces, film on the streets, have the cooperation of the police, you have to have a permit.
We're taught Lord Acton's axiom: all power corrupts, absolute power corrupts absolutely. I believed that when I started these books, but I don't believe it's always true any more. Power doesn't always corrupt. Power can cleanse. What I believe is always true about power is that power always reveals.