A downhole fluid properties optical analysis probe (1) to analyze at least one property of a multiphase flow mixture (100) flowing in a hydrocarbon well (51) has an elongated cylindrical body shape. It comprises an optical tip (5) at one end of the elongated cylindrical body arranged to be in contact with the multiphase flow mixture (100). It further comprises an optical link (6) adapted for a connection with an electronics module (11) at another end of the elongated cylindrical body arranged to be separated from the multiphase flow mixture (100). The optical tip (5) is coupled to the optical link (6) through a removable and watertight coupling (7). The removable and watertight coupling comprises a first portion (9a) of a protective tube (9) resistant to downhole conditions, said first portion (9a) enclosing the optical link (6) and comprising at least one first ring bulge (22) close to a coupling interface (10), and a second portion (9b) of the protective tube (9) partially enclosing the optical tip (5) such as to let a distal end of the optical tip (5) in contact with the multiphase flow mixture (100), said second portion (9b) comprising at least one second ring bulge (23) close to the coupling interface (10). It further comprises a coupling tube (24) surrounding facing ends of the first portion (9a) and the second portion (9b), said coupling tube (24) being adjusted in size to fit in between said first and second ring bulges (22, 23), and a coupling and protecting sheath (25) enclosing said first ring bulge (22), coupling tube (24) and second ring bulge (23) in a watertight manner.