  We report on the discovery of a new fast radio burst, FRB 150215, with the
Parkes radio telescope on 2015 February 15. The burst was detected in real time
with a dispersion measure (DM) of 1105.6$\pm$0.8 pc cm^{-3}, a pulse duration
of 2.8^{+1.2}_{-0.5} ms, and a measured peak flux density assuming the burst
was at beam center of 0.7^{+0.2}_{-0.1} Jy. The FRB originated at a Galactic
longitude and latitude of 24.66^{\circ}, 5.28^{\circ}, 25 degrees away from the
Galactic Center. The burst was found to be 43$\pm$5% linearly polarized with a
rotation measure (RM) in the range -9 < RM < 12 rad m^{-2} (95% confidence
level), consistent with zero. The burst was followed-up with 11 telescopes to
search for radio, optical, X-ray, gamma-ray and neutrino emission. Neither
transient nor variable emission was found to be associated with the burst and
no repeat pulses have been observed in 17.25 hours of observing. The sightline
to the burst is close to the Galactic plane and the observed physical
properties of FRB 150215 demonstrate the existence of sight lines of
anomalously low RM for a given electron column density. The Galactic RM
foreground may approach a null value due to magnetic field reversals along the
line of sight, a decreased total electron column density from the Milky Way, or
some combination of these effects. A lower Galactic DM contribution might
explain why this burst was detectable whereas previous searches at low latitude
have had lower detection rates than those out of the plane.
