Denis Burgarella (OAMP) Herschel FIR detection of a population of IR-bright Lyman Break Galaxies at 0.5 < z < 4 Lyman Break Galaxies are selected by their UV color and they provided the astronomers with the first (and still) largest sample of high redshift galaxies. Their ultraviolet and optical properties are rather well constrained and they appear to be starburst galaxies. However, since the very beginning, one question was not satisfactorily addressed: what is their infrared luminosity or, in other words, how much dust attenuation is necessary to evaluate their total star formation rate (SFR)? Spitzer and AKARI allowed us to start addressing this point. Herschel, with its 3.5m-diameter telescope (almost as large as CFHT) is going one step further and we start detecting some of them at z > 3. We will report on these detections and try to understand what they mean in terms of galaxy evolution.