Portable electronic device capable of processing information, said portable electronic device including a body arranged to be capable of being secured to the user, and at least one electronic assembly for processing information, the body of the portable electronic device being formed by a layer of plastic material which gives the portable electronic device a shape and thickness, characterized in that the portable electronic device includes a first impermeable plastic film which serves as a coating for the layer of plastic material, and a second impermeable plastic film secured to the periphery of the first impermeable plastic film, and in that the electronic assembly for processing information is arranged between the first and second impermeable plastic films.The invention also concerns a method of manufacturing a portable electronic device.