PC 415 (public disturbance)

Any of the following persons shall be punished by imprisonment
in the county jail for a period of not more than 90 days, a fine of
not more than four hundred dollars ($400), or both such imprisonment
and fine:
  (1) Any person who unlawfully fights in a public place or
challenges another person in a public place to fight.
  (2) Any person who maliciously and willfully disturbs another
person by loud and unreasonable noise.
  (3) Any person who uses offensive words in a public place which
are inherently likely to provoke an immediate violent reaction.

PC 415 can be tried as a misdemeanor or as an infraction.  Ideally
you get the misdemeanor knocked down to an infraction, but this is
not always the case. 
Unlawfully fights generally means that there was no consent to the
fight or that the individuals involved in the fight did not agree
to the conduct.  For (2) malicious and willful the person must have
intended to disturb the person and did it for an "evil" purpose. 
For (3) offensive need not be swear words but words intended to provoke
a violent response from the victim.