Know Your Protest Rights
From the ACLU:
You don’t need a permit to protest in response to breaking news and you don’t need a permit to march in the streets or along sidewalks, as long as you’re not obstructing traffic or access to buildings.
When you are lawfully present in any public space, you have the right to photograph anything in plain view, including federal buildings and the police.
If you believe your rights have been violated, when you can, write down everything you remember, get contact information for witnesses, and take photographs of any injuries.
If you get stopped by the police, ask if you’re free to go. If they say yes, calmly walk away.
If you get arrested, you have the right to ask why. Otherwise, say you wish to remain silent and ask for a lawyer immediately. Don’t sign, say or agree to anything without a lawyer present.
If you get stopped by a member of the military or any law enforcement officer at a protest, you have the right to remain silent or to tell them that you’ll only answer questions in the presence of an attorney -no matter your citizenship or immigration status.