  This paper describes the first data release (DR1) of the VIMOS Ultra Deep
Survey (VUDS). The DR1 includes all low-resolution spectroscopic data obtained
in 276.9 arcmin2 of the CANDELS-COSMOS and CANDELS-ECFDS survey areas,
including accurate spectroscopic redshifts z_spec and individual spectra
obtained with VIMOS on the ESO-VLT. A total of 698 objects have a measured
redshift, with 677 galaxies, two type-I AGN and a small number of 19
contaminating stars. The targets of the spectroscopic survey are selected
primarily on the basis of their photometric redshifts to ensure a broad
population coverage. About 500 galaxies have z_spec>2, 48 with z_spec>4, and
the highest reliable redshifts reach beyond z_spec=6. This dataset
approximately doubles the number of galaxies with spectroscopic redshifts at
z>3 in these fields. We discuss the general properties of the sample in terms
of the spectroscopic redshift distribution, the distribution of Lyman-alpha
equivalent widths, and physical properties including stellar masses M_star and
star formation rates (SFR) derived from spectral energy distribution fitting
with the knowledge of z_spec. We highlight the properties of the most massive
star-forming galaxies, noting the large range in spectral properties, with
Lyman-alpha in emission or in absorption, and in imaging properties with
compact, multi-component or pair morphologies. We present the catalogue
database and data products. All data are publicly available and can be
retrieved from a dedicated query-based database available at
http://cesam.lam.fr/vuds.
