The invention relates to a method of discrimination in spectrometry, particularly of eliminating phenomena of fluorescence in Raman spectrometry. According to the invention, a sample (6) is excited by a luminous pulse (5) generated from a laser (1). The light (7) emitted by the sample (6) is directed into an interferometer (8) of which the duration of a round trip of a luminous ray is significantly longer than the duration of the pulse of the incident wave and shorter than the duration of the phenomenon of fluorescence. The resulting light (9) is then directed to a second interferometer (10) of which the optical path is slightly different from that of the preceding interferometer (8). The light (11) is recovered at the outlet of the second interferometer (10) and this wave is analyzed by means of a spectrometer (12). The invention is applicable particularly to the analyzing of samples in the chemical industry.