Cal. BPC § 4999.27

(a) Nothing in this chapter shall restrict or prevent activities of a psychotherapeutic or counseling nature on the part of persons employed by accredited or state-approved academic institutions, public schools, government agencies, or nonprofit institutions who train graduate students pursuing a degree that qualifies for professional clinical counselor licensure at an accredited or state-approved college or university, provided that these activities and services constitute a part of a supervised course of study and that those persons are designated by a title such as “clinical counselor trainee” or other title clearly indicating the training status appropriate to the level of training.

(b) Notwithstanding subdivision (a), a graduate student shall not perform professional clinical counseling in a private practice or a professional corporation.