  The FCC-ee accelerator is considered within the FCC design study as a
possible first step towards the ultimate goal of a 100 TeV hadron collider. It
is a high luminosity e+e- storage ring collider, designed to cover energies of
around 90, 160, 240 and 350GeV ECM (for the Z peak, the WW threshold, the ZH
and ttbar cross-section maxima respectively) leading to different operating
modes. We report on the current status of the design study, on the most
promising concepts and relevant challenges. The expected luminosity performance
at all energies, and first studies on transverse polarization for beam energy
calibrations will be presented.
