The invention relates to the use of a block copolymer having at least one block that comprises phosphate and/or phosphonate functions, as an additive for film-forming compositions, such as paint, latex or mastic which is optionally siliconised in order to ensure or promote the adhesion of the aforementioned compositions on a metallic surface or to protect said metallic surface against corrosion. The invention also relates to film-forming compositions comprising the abovementioned block copolymers.