The flux distribution delivered by a Fresnel lens when concentrating solar energy is characterized. The flux is measured with a Si photo-detector equipped with an integrating sphere. Flux mapping is performed by scanning lines at discrete positions on one plane. The peak concentration is determined as well as the distribution of the flux density in 3-D inside the focal area. Future utilization of this Fresnel lens for solar processing and surface modifications of materials is discussed.. The analysis is made on the basis of the optical characteristics of the device and of the results of previous works in the same field. The size of the focus and the peak flux density are key parameters for examining the candidate processing and for discussing the dimensions of the treated components.