Fiber optic probes can be used to evaluate flow properties in gas-solid and gas-liquid-solid systems. In this study, the local flow structure of bubbling flow was investigated in a slurry bubble column and in a fluidized bed. The bubble flow characteristics could, therefore, be determined along the bed cross section in various operating conditions. In both systems, the results were validated by independent measurements. Comparison of the radial profiles of bubble hold-up obtained in the slurry bubble column and in the gas-solid fluidized bed surprisingly showed quantitative agreement. Further investigations are required at different scales, but this result supports already proposed analogies between the two systems.