Filing a false police report in California can subject the reporting person to a criminal charge by the State.
The reporting person, however, is absolutely immune from civil liability to the person whom the report concerned in a case like this pursuant to California Civil Code section 47(b).
They don't want to discourage people from filing police reports. They assume the police will investigate the legitimacy of the complaint.
If the case should go to trial and the person is found not guilty on the merits of the case, then an action may lie for malicious prosecution.