PLÉIADES is an ultra high resolution soft X-ray beamline (ultimate resolving power of about 100000 at 50 eV) covering the energy domain ranging from 10 eV to 1 keV. PLÉIADES is dedicated to spectroscopy based atomic and molecular physics studies of diluted samples (atoms, molecules, ions, clusters, molecules adsorbed on surfaces). All horizontal, vertical and tilted linear polarizations, as well as circular and elliptical polarizations, are available starting from 55 eV thanks to a permanent magnet (80 mm period) Apple II type of undulator. Linear horizontal and vertical polarized beams are available as low as 10 eV from a 2nd (256 mm period) electromagnetic undulator. In the beamline design, particular care has been taken in order to obtain a very high spectral purity soft X-ray beam : thanks to an appropriate combination of quasi-periodic design for the undulators and the use of a varied groove depth (VGD) for the plane grating, higher orders are very efficiently rejected (usually less than 0.5%). A high resolution electron spectrometer, an energy and angle Auger electron - ion coincidence setup (EPICEA), as well as a dedicated station (MAIA) for positive and negative ion photoionization studies (ECR source) are permanently installed on the beamline. Moreover, a conventional laser facility (c.w. and pulsed), as well as the possibility of combining high intensity/high repetition rate (1 mJ/100 kHZ, 5 mJ/20 kHZ, 10 mJ/10 kHZ) femtosecond laser pulses from an in-house facility to the synchrotron beam in pump-probe schemes will also be offered to the users in the near future. The beamline has three optical branches with different focusing properties of the beam. Two of them (branch N°2 and N°3) are offering the external users the possibility of installing their own setups (see table below for spot sizes and beam divergences on sample).