As a prerequisite for a lawsuit for sexual harassment in California, a potential plaintiff is required to get a right to sue letter from either the California Department of Fair Employment and Housing (DFEH) or the Federal Equal Employmnet Opportunity Commission (EEOC).
See the statutes of limitation article in this website for the applicable statutes of limitation; https://sexualharassmentlawyerscalifornia.com/statutes-of-limitation-how-much-time-you-have-to-bring-a-claim/
If an administrative claim to the DFEH or the EEOC is not filed within the time period provided by the applicable statute of limitations, then the case is subject to being forever barred by the courts. If a sexual harassment victim does not file an administrative complaint within the required amount of time, then that victim will not be able to move forward with a lawsuit.
To file a lawsuit in California Superior Court, a victim must first file a complaint with the DFEH within three years from the date of the last incident of sexual harassment, which period may be extended up to 90 days if the alleged victim first obtained knowledge of the facts of the harassment after the expiration of the three year period from the date of the occurrence.
After a claimant files an administrative complaint and after the claimant gets a right to sue letter, then the claimant must file a private civil lawsuit within the time specified in the right to sue letter, which is within one year of the date of a right to sue letter from the DFEH.