[en] When used in lead-scintillator sandwich calorimetry, scintillating optical fibres offer a new way to achieve fine grain sampling and thereby to improve the energy and spatial resolution of a technique still unbeaten for timing and compactness. A small calorimeter element made of planes of 0.9 mm diameter fibres alternating with Pb plates has been built and tested in an electron beam. An energy resolution of sigmasub(E)/√E approx.= 9.8 and 7.8% was obtained with 1 and 0.5 mm Pb plates, respectively. The parameters of the fibres have been measured. Calculations performed with a refined version of the EGS code reproduce these results and suggest improved Pb-fibre calorimeters rivalling with Pb glass in energy resolution. (orig.)