Magnetic susceptibility, Hall effect and resistivity of narrow-gap Ge 1−x−y Sn x Mn y Te single crystals (x = 0.083 ÷ 0.115; y = 0.025 ÷ 0.124) were investigated in the temperature range 4.2-300 K revealing a ferromagnetic ordering at T C ≈ 50 K. Temperature dependence of magnetization indicates a superparamagnetic phase with magnetic clusters arranging in a spin glass state below the freezing temperature T f . Magnetic structure of InSe Mn 2D-ferromagnetic single crystals was studied by SQUID magnetometry, neutron diffraction, secondary ion mass spectroscopy, and wave dispersive spectra. Hysteresis loops of magnetization were observed at least up to 350 K. The cluster model of ferromagnetism is considered. The formation of self-assembled superlattice ferromagnetic InSe:Mn/antiferromagnetic MnSe during growth process and further annealing was established.