Following my junior year in high school, I went on a camping trip through Russia in a group led by Horst Momber, a young language teacher from Roosevelt.
You go out with a girl you used to date, she looks so damn good, and then at a certain point you say, Boy, now I remember. I know why I left!
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.