Abstract: In order to coat with a uniform metal deposit the fibres of slivers to be used in the production of composite materials with a metallic or non-metallic matrix, it is proposed to use a spread fibre sliver (30) wound onto a feed spool (28) with an interpolated sheet (32). In order to avoid the deformation of the spread sliver, the latter is unwound by pulling on the interpolated sheet by means of an interpolated sheet receiving spool (34) driven by a motor (M1). Thus, the sliver travels by gravity in front of metallization means, such as rotary magnetron cathodes (40a, 40b). It is then rewound, together with a second interpolated sheet (46) onto a spool (42) driven by a motor (M2) via a brake (43) having a very limited torque.