The exciton luminescence of CdTe based quantum well structures with the embedded ultrathin MnTe layers is studied. It appears that the energy position and width of the exciton emission bands as well as their lifetime and temperature behavior depend strongly on the real profiles of manganese distribution in the direction of the structure growth. The relative contributions of free and localized states to the low temperature exciton luminescence show that the manganese incorporation is favorable to smooth the CdTe/Cd1-xMgxTe interfaces.