Three different sites of the Cr 3ϩ ions in the fluoride perovskite KMgF 3 have been identified by absorption, selective optical excitation, and time-resolved emission spectroscopy of the 4 T 2 ↔ 4 A 2 transition. Highpressure measurements showing the crossover from low-crystal field to high-crystal field, allows us to situate the Dq/B values of the different chromium sites clearly below 2.3. The different spin-orbit components associated with the zero-phonon lines of the 4 T 2 ↔ 4 A 2 transition of each type of site are clearly shown on the optical spectra and identified by group-theory analysis. The decay profiles of the 4 T 2 level are exponential and the lifetimes at 15 K are 903, 919, and 473 s for the cubic, quadratic, and trigonal sites, respectively. The trigonal center which presents the lowest energy levels was peculiarly studied. Emission and excitation spectra are compared; their evolution versus temperature is followed and explained by the thermal population of the different spin-orbit sublevels. The phonon sideband of the trigonal site is compared with our previous lattice dynamic studies of the pure compound. The different peaks of the emission broadband are described in terms of phonons of the matrix and normal modes of the ͓CrF 6 ͔ 3Ϫ complex. ͓S0163-1829͑97͒03430-9͔