Most of the time, it can be fixed without a lawsuit. A lot of people on OCDO here in Idaho and elsewhere have changed company and government policies. Is this a city law? I would suggest writing a letter to the city council to start with. Explain your the law and your position and ask that it be repealed. Also write the police and ask them if they intend to enforce this law (we have laws here in Boise that are still on the books, but unenforceable because of the new state preemption).
If that doesn't work, I'd suggest actually attending a meeting, with several other people in support of you. We'd have to take it from there but I think this is a good start.