In Baron v. City of Los Angeles (1970) 2 Cal.3d 535, the court considered whether a Los Angeles city ordinance requiring lobbyists to register was void for attempting to regulate the practice of law, a field preempted by state law. It held the ordinance could be not be applied to attorneys when they were engaged in activities which can only be performed by a licensed attorney, but was otherwise applicable to lawyers. As an example, the court said an attorney representing a client at a quasi-judicial hearing was exempt, but "an attorney authorized by a client to appear at hearings considering local legislation in order to argue for or against the adoption of that legislation would be within the legitimate thrust of the ordinance." ( Id. at p. 544.)