A series of borogermanate glasses with CsPbBr3 perovskite nanocrystals and Eu3+ ions is synthesized. At low concentrations of Eu2O3 in glass, Eu3+ ions play the role of crystallization centers for the nucleation of perovskite nanocrystals. At high concentrations of Eu2O3 in glass, CsPbBr3 nanocrystals nucleate only during additional heat treatment. The lifetime of Eu3+ luminescence increases from 1.58 to 1.69 msec along with an increase in the Eu2O3  concentration. Along this, a slight distortion of the Eu3+ environment occurs in the glass matrix, resulting in a slight redistribution of the characteristic luminescence bands.