Résumé
Bernard Laffaille and Nicolas Esquillan were two main actors of shell and spatial structures design during the twentieth century. Their respective works crossed each other during the CNIT project for which they submitted two different solutions as mentioned in this paper. Pioneer of cable nets, Bernard Laffaille tried then to improve this innovative lightweight solution in his last projects. Nicolas Esquillan, who won the CNIT contest, can be doubtless considered as a pioneer of reinforced concrete shells, and contributed to the shell and spatial structures knowledge, working closely with Eduardo Torroja at the early years of the International Association for Shell and Spatial Structures.