An impregnated fibrous material comprising a fibrous material made of continuous fiber and at least one thermoplastic polymer matrix, wherein the at least one thermoplastic polymer is an non-reactive amorphous polymer, the glass transition temperature of which is such that Tg≥80° C., or a non-reactive semi-crystalline polymer, the melting temperature of which is Tf≥150° C., the fiber volume ratio is constant in at least 70% of the volume of the tape or ribbon, the fiber ratio in the pre-impregnated fibrous material ranging from 45 to 65% by volume, the porosity rate in the pre-impregnated fibrous material being less than 10%.