The extremely high brilliance X-ray beams produced by the European X-ray Free-Electron Laser (European XFEL) facility present very demanding requirements to beam conditioning optical components. In particular, hard X-ray monochromator optics which is used to reduce intrinsic bandwidth of SASE X-rays, must withstand extreme heat loads and maintain the positional stability of the monochromatic beam. The design based on artificial channel-cut monochromator (ACCM) optics [1] has been implemented at European XFEL. Due to high quality polished single Si crystals and cryogenic cooling the ACCM monochromator devices enable wavefront-preserving monochromatization of XFEL beam.