A method of transferring a portion of a functional film (1) onto a substrate from a base plate (100) comprises the formation of a groove (S1) which passes through the said functional film and also a separating film (2) placed between the functional film and the base plate. A portion (2p) of the separating film is then detached from the base plate with the portion of the functional film. The portion of said separating film protects the portion of the functional film in the rest of the method. According to one improvement, the portion of the functional film which is detached from the base plate comprises a useful portion (1p) and a margin (1m) that are connected together by the portion (2p) of the separating film. The useful portion (1p) of the functional film may then be gripped and handled via the margin (1m).