  We present the first high spatial and spectral observations of the
circumstellar envelope (CSE) of a B[e] supergiant (CPD$-57 2874$), performed
with the Very Large Telescope Interferometer (VLTI). Spectra, visibilities, and
closure phase, were obtained using the beam-combiner instruments AMBER (near-IR
interferometry with three 8.3 m Unit Telescopes or UTs) and MIDI (mid-IR
interferometry with two UTs). The interferometric observations of the CSE are
well fitted by an elliptical Gaussian model with FWHM diameters varying
linearly with wavelength. Typical diameters measured are $\simeq1.8\times3.4$
mas or $\simeq4.5\times8.5$ AU (adopting a distance of 2.5 kpc) at
$2.2\micron$, and $\simeq12\times15$ mas or $\simeq30\times38$ AU at
$12\micron$. The size of the region emitting the Br$\gamma$ flux is
$\simeq2.8\times5.2$ mas or $\simeq7.0\times13.0$ AU. The major-axis position
angle of the elongated CSE in the mid-IR ($\simeq144\degr$) agrees well with
previous polarimetric data, hinting that the hot-dust emission originates in a
disk-like structure. In addition to the interferometric observations we also
present new optical ($UBVR_{c}I_{c}$) and near-IR ($JHKL$) broadband
photometric observations of CPD$-57 2874$. Our spectro-interferometric VLTI
observations and data analysis support the non-spherical CSE paradigm for B[e]
supergiants.
