  With the release of the first year Fermi catalogue, the number of blazars
detected above 100 MeV lying at high redshift has been largely increased. There
are 28 blazars at z>2 in the "clean" sample. All of them are Flat Spectrum
Radio Quasars (FSRQs). We study and model their overall spectral energy
distribution in order to find the physical parameters of the jet emitting
region, and for all of them we estimate their black hole masses and accretion
rates. We then compare the jet with the accretion disk properties, setting
these sources in the broader context of all the other bright gamma-ray or hard
X-ray blazars. We confirm that the jet power correlates with the accretion
luminosity. We find that the high energy emission peak shifts to smaller
frequencies as the observed luminosity increases, according to the blazar
sequence, making the hard X-ray band the most suitable for searching the most
luminous and distant blazars.
