A biodegradable three-layer polyester film of 8 to 20 μm in thickness having a layer construction A/B/C or preferably A/B/A, wherein the two outer layers or (A, C) are composed of: Ai) 55% to 99.99% by weight based on the polyester mixture of the outer layers of a polyester selected from the group consisting of: polybutylene sebacate-co-terephthalate, polybutylene sebacate-co-adipate-co-terephthalate, polybutylene sebacate-co-succinate-co-terephthalate or mixtures thereof or a mixture of polybutylene sebacate-co-terephthalate and polybutylene adipate-co-terephthalate; Aii) 0.01% to 5% by weight based on the polyester mixture of the outer layers of at least one additive selected from the group consisting of: a wax, a plasticizer, a nucleating agent, antifogging agent, filler and an antiblocking agent; and Aiii) 0% to 44.99% by weight based on the polyester mixture of the outer layers of a further biodegradable polymer selected from the group consisting of: polylactic acid, polycaprolactone, polyhydroxyalkanoate, polypropylene carbonate or polyester produced from aliphatic dicarboxylic acids and an aliphatic dihydroxy compound; and the middle layer B is composed of: Bai) 40% to 75% by weight based on the mixture of the middle layer of a biodegradable aliphatic-aromatic polyester; Baii) 25% to 40% by weight based on the mixture of the middle layer of starch having a plasticizer content of 0% to 5% by weight based on the total weight of the component Baii); and Baiii) 0% to 20% by weight based on the mixture of the middle layer of a further biodegradable polymer selected from the group consisting of: polylactic acid, polycaprolactone, polyhydroxyalkanoate, polypropylene carbonate or polyester produced from aliphatic dicarboxylic acids and an aliphatic dihydroxy compound; or Bbi) 25% to 70% by weight based on the mixture of the middle layer of a biodegradable aliphatic-aromatic polyester; Bbii) 30% to 55% by weight based on the mixture of the middle layer of starch having a plasticizer content of 5% to 35% by weight based on the total weight of the component Bbii); and Bbiii) 0% to 20% by weight based on the mixture of the middle layer of a further biodegradable polymer selected from the group consisting of: polylactic acid, polycaprolactone, polyhydroxyalkanoate, polypropylene carbonate or polyester produced from aliphatic dicarboxylic acids and an aliphatic dihydroxy compound. Ai) 55% to 99.99% by weight based on the polyester mixture of the outer layers of a polyester selected from the group consisting of: polybutylene sebacate-co-terephthalate, polybutylene sebacate-co-adipate-co-terephthalate, polybutylene sebacate-co-succinate-co-terephthalate or mixtures thereof or a mixture of polybutylene sebacate-co-terephthalate and polybutylene adipate-co-terephthalate; Aii) 0.01% to 5% by weight based on the polyester mixture of the outer layers of at least one additive selected from the group consisting of: a wax, a plasticizer, a nucleating agent, antifogging agent, filler and an antiblocking agent; and Aiii) 0% to 44.99% by weight based on the polyester mixture of the outer layers of a further biodegradable polymer selected from the group consisting of: polylactic acid, polycaprolactone, polyhydroxyalkanoate, polypropylene carbonate or polyester produced from aliphatic dicarboxylic acids and an aliphatic dihydroxy compound; Bai) 40% to 75% by weight based on the mixture of the middle layer of a biodegradable aliphatic-aromatic polyester; Baii) 25% to 40% by weight based on the mixture of the middle layer of starch having a plasticizer content of 0% to 5% by weight based on the total weight of the component Baii); and Baiii) 0% to 20% by weight based on the mixture of the middle layer of a further biodegradable polymer selected from the group consisting of: polylactic acid, polycaprolactone, polyhydroxyalkanoate, polypropylene carbonate or polyester produced from aliphatic dicarboxylic acids and an aliphatic dihydroxy compound; or Bbi) 25% to 70% by weight based on the mixture of the middle layer of a biodegradable aliphatic-aromatic polyester; Bbii) 30% to 55% by weight based on the mixture of the middle layer of starch having a plasticizer content of 5% to 35% by weight based on the total weight of the component Bbii); and Bbiii) 0% to 20% by weight based on the mixture of the middle layer of a further biodegradable polymer selected from the group consisting of: polylactic acid, polycaprolactone, polyhydroxyalkanoate, polypropylene carbonate or polyester produced from aliphatic dicarboxylic acids and an aliphatic dihydroxy compound.