Abstract: New process, for preparing by means of a paper manufacturing technique, a thermoplastic sheet reinforced with cellulose fibres, wherein a thermoplastic powder and cellulose fibres are used in association, if necessary with other fibres, and consisting in (1) preparing an aqueous suspension from a base mixture (selected among (i) the fibres and the pulverulent thermoplastic substance when there is no non-binding mineral charge, and (ii) the fibres, the pulverulent thermoplastic substance and the non-binding mineral char harge when the latter is present), an organic binder and a flocculating agent, and with the resulting suspension, forming a sheet by wet process, which is then wrung and dried and (2) if necessary subjecting the resulting thermoplastic sheet to at least a complementary treatment, the weight ratio of pulverulent thermoplastic substance to fibres being between 0.3 and 95.