The invention seeks to provide a magnetized coating suitable for exerting durable magnetic forces. To do this, the method of the invention consists in spreading conductive particles (13) on a medium (11), the particles being directed by prior magnetization along an inducing magnetic field and being embedded in a binder (12). The coating apparatus for implementing the method of the invention comprises means (10, 15) for feeding the medium (11) onto a conveyor (20), means for applying a main binder (12) via presser rollers (40) and via at least one nozzle (30), said means being coupled to heater means, a tank (50) of particles (13) coupled to a duster (51) for dispensing the fill of particles, means for spreading the fill of particles within the main binder, electromagnetic means (60) for producing an anisotropic magnetic field for magnetizing the particles, a sprayer (80) for depositing an additional binder, dryer means (100), demagnetizer means (110), and winder means (120). The invention is applicable to media particularly in paper-making, games, decoration, or building.