The present invention relates to a fluid treatment chamber with a self-cleaning rotary sight window. The proposed rotary sight window includes a stationary frame (10); a transparent stationary panel (11) attached to the stationary frame by a leak-tight joint (41); a rotary frame (20) connected to the stationary frame (10) by a rotary joint (40); a transparent rotary panel (21) attached to the rotary frame (20) by a joint, the transparent rotary panel (21) being arranged opposite and spaced apart from the transparent stationary panel (11) by an intermediate chamber (1); and a motor (30) connected to the transparent rotary panel (21) or to the rotary frame (20), wherein the joint between the transparent rotary panel (21) and the rotary frame (20) is an interference joint (43) attached by a dimensional interference fit.