  We present here the first abundance analysis of 44 late B, A and F-type
members of the young open cluster M6 (NGC 6405, age about 75 Myrs). Spectra,
covering the 4500 to 5800 \AA{} wavelength range, were obtained using the
FLAMES/GIRAFFE spectrograph attached to the ESO Very Large Telescopes (VLT). We
determined the atmospheric parameters using calibrations of the Geneva
photometry and by adjusting the $H_{\beta}$ profiles to synthetic ones. The
abundances of up to 20 chemical elements, were derived for 19 late B, 16 A and
9 F stars by iteratively adjusting synthetic spectra to the observations. We
also derived a mean cluster metallicity of $\mathrm{[Fe/H]=0.07\pm0.03}$ dex
from the iron abundances of the F-type stars. We find that, for most chemical
elements, the normal late B and A-type stars exhibit larger star-to-star
abundance variations than the F-type stars do probably because of the faster
rotation of the B and A stars. The abundances of C, O, Mg, Si and Sc appear to
be anticorrelated to that of Fe, while the opposite holds for the abundances of
Ca, Ti, Cr, Mn, Ni, Y, and Ba about as expected if radiative diffusion is
efficient in the envelopes of these stars. In the course of this analysis, we
discovered five new peculiar stars: one mild-Am, one Am, and one Fm star (HD
318091, CD-32 13109, GSC 07380-01211), one HgMn star (HD 318126), and one
He-weak P-rich (HD 318101) star. We also discovered a new spectroscopic binary,
most likely a SB2. We performed a detailed modelling of HD 318101,the new
He-weak P-rich CP star, using the Montr\'eal stellar evolution code XEVOL which
treats self-consistently all particle transport processes. Although the overall
abundance pattern of this star is properly reproduced, we find that detailed
abundances (in particular the high P excess) resisted modelling attempts even
when a range of turbulence profiles and mass loss rates were considered.
