This paper presents the physicochemical characteristics of CeF3 nanopowder (NP) obtained via electron evaporation. The initial NP was annealed in air (200–500 °C) for 30 min. The annealed NP was evaluated using the following methods: X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), differential scanning calorimetry-thermogravimetry (DSC-TG) and luminescence/magnetic measurements. The degree of cytotoxicity of CeF3 nanoparticles (NPles) to cell cultures was determined. The cubic phase CeO2 formed in CeF3 NP after annealing (500 °C). The appearance of the CeO2 oxide phase led to an increase in the intensity of photoluminescence. Cathodoluminescence was not excited. The paramagnetic response of NPles decreased with an increase in the annealing temperature. Cerium fluoride NPles showed low cytotoxicity towards cancerous and non-cancerous cells. Annealing of the CeF3 NP at low temperatures led to an improvement in the textural parameters of the not annealed NP. Improved texture parameters indicate the prospect of using CeF3 as a biomedicine nanocontainer.