Polarization properties of the fluorescence induced by polarized laser radiation are widely considered in laboratory studies. In lidar observations, however, only the total scattered power of fluorescence is analyzed. In this paper we present results obtained with a modified Mie-Raman-Fluorescence lidar operated at the ATOLL observatory, Laboratoire d'Optique Atmosphérique, University of Lille, France, allowing to measure depolarization ratios of fluorescence at 466 nm (δF) and of water vapor Raman backscatter. Measurements were performed in May-June 2023 during Alberta forest fires season when smoke plumes were almost continuously transported over the Atlantic Ocean towards Europe. During the same period, smoke plumes from the same sources were also detected and analyzed in Moscow, at General Physics Institute (GPI), with a 5-channel fluorescence lidar able to measure fluorescence backscattering at 438, 472, 513, 560 and 614 nm. Results demonstrate that, inside the boundary layer (BL), urban aerosol fluorescence is maximal at 438 nm, then it gradually decreases with wavelength. Results also show that the maximum of the smoke fluorescence spectrum shifted towards longer wavelengths. The smoke layers observed within 4-6 km present a maximum of fluorescence at 513 nm while, in the upper troposphere (UT), the maximum shifts to 560 nm. Regarding fluorescence depolarization, its value typically varies inside the 45-55 % range, however several smoke plume layers detected above 10 km were characterized by a δF increasing up to 70%. Inside the BL, the fluorescence depolarization ratio was higher than that of smoke and varied inside the 50-70% range. Moreover, in the BL, δF appears