A process for depositing a coating on short fibres of carbon or silicon carbide from a coating precursor, the short fibres having a length of between 50 μm and 5 mm, the process including at least heating the short fibres by placing a mixture including the fibres and a liquid phase of the coating precursor in a microwave field so as to bring the surface of the fibres to a temperature allowing the coating on the fibres from the coating precursor to be formed by calefaction.