  AIMS: Using Wide-field Infrared Survey Explorer (WISE) data and previous
optical and near-infrared sky surveys, we try to identify still missing stellar
and substellar neighbours of the Sun. METHODS: When checking the brightest red
WISE sources for proper motions and colours expected for nearby M and L dwarfs
we also approached the thin Galactic plane. Astrometry (proper motion and
parallax measurements) and the available photometry were used to give first
estimates of the distance and type of nearby candidates. RESULTS: We have
discovered WISE J072003.20$-$084651.2, an object with moderately high proper
motion ($\mu$$\approx$120 mas/yr) and at low Galactic latitude
($b$$=$$+$2.3$\degr$), with similar brightness ($J$$\approx$10.6,
$w2$$\approx$8.9) and colours ($I$$-$$J$$\approx$3.2, $J$$-$$K_s$$\approx$1.2,
$w1$$-$$w2$$\approx$0.3) as the nearest known M-type brown dwarf LP 944-20.
With a photometric classification as an M9$\pm$1 dwarf, its photometric
distance lies in the range between about 5 and 7 pc, based on comparison with
absolute magnitudes of LP 944-20 alone or of a sample of M8-L0 dwarfs.The
slightly larger distance derived from our preliminary trigonometric parallax
(7.0$\pm$1.9 pc) may indicate a close binary nature. The new neighbour is an
excellent target for planet search and low-mass star/brown dwarf studies.
