Legal Question in Constitutional Law in California

First Amendment rights can be expensive and time-consuming to assert. Ask other artists what is allowed in your community. Not to say you shouldn't fight City Hall in appropriate cases, but know what you're getting into.

The First Amendment does not grant an absolute right to free speech at any time in any place and by any method. A huge body of law has evolved over what restrictions are allowed on the time place and manner of free speech, including displays of art. There is no doubt you can stand on a street corner holding a piece of your art for others to see. Once you start setting up displays, or tables, or working on your art in a way that consumes public space, you head down the road into the maze of laws balancing free speech with the power of the state to control its streets, sidewalks and other public places. Commercial speech is much less protected than other kinds of speech as well, so once you are selling art as opposed to just displaying it, or start working on your art in public you come under much less protection and therefore much more restriction is allowed. Pretty much every local government has time place and manner restrictions on free speech and commercial speech in their local ordinances and regulations. Most of those ordinances and regulations have been well vetted by attorneys or copied from other cities whose speech regulations have been thoroughly vetted or even litigated and upheld. So your chances of challenging them on First Amendment grounds is about zero. The bottom line is find out what the local rules are and follow them.