This invention relates to a coextruded, transparent, biaxially oriented polyester film comprising a base layer (B) and a heatsealable top layer (A) which is peelable from at least APET, the heatsealable and peelable top layer (A) consisting of a) 60 97% by weight of polyester and b) 3 30% by weight of a polyester-incompatible polymer (=anti-PET polymer), based on the mass of the top layer (A), wherein c) the polyester being composed of 25 95 mol % of units which derive from at least one aromatic dicarboxylic acid and 5 75 mol % of units which derive from at least one aliphatic dicarboxylic acid, the sum of the dicarboxylic acid-derived molar percentages being 100, and d) the layer thickness of the top layer (A) d.sub.A being from 0.7 to 2.5 .mu.m.