Incorrect answer.
Mayors and governors both can declare states of emergencies that effect their jurisdictions. It is not the same as a federal state of emergency in the scope or severity of what is restricted obviously. Generally when it's declared locally it is due to some form of natural disaster in an attempt to help clear it up and pave the way for federal funds but it can be used in other ways also such as civil unrest. I am in no way saying the use was appropriate here and this is not what it is intended to be used for but that is for the courts to decide
I think if this ever ends up in court, that the Chief of Police (acting mayor) and the City Council will be in for a nasty suprise.
The Chief of Police, seems to be arrogant to the point of delusion. Does he really think he will ultimately get away with this shit??