Flexible implant for focal stimulation or electrical recording of a nerve structure of an organ of interest, comprising: - at least one outer layer of biocompatible polymer, - a first layer of electrically insulating diamond, - at least one electrode of electrically conductive doped diamond in contact with the first layer of electrically insulating diamond, located at a first opening, - an electrically conductive layer of metal or electrically conductive doped diamond, in contact with: - the electrode, and - the first layer, to define a conductive track per electrode; - a second layer of electrically insulating diamond at least in contact with the electrically conductive layer and a remaining part of the first layer, arranged so that: - an electrically insulating diamond/electrically conductive doped diamond seal is made at the electrode by epitaxial growth; - the electrically conductive layer is encapsulated by: • the electrode, the first layer and the second layer at the electrode, and • the first layer, and the second layer, over its entire remaining surface, except for an area located at a second opening defining an electrical contact by electrode for connecting the flexible implant via the electrically conductive layer to an electronic component to control the electrical coupling between the electrode and the nerve structure, the flexible implant with two faces: - a front face having one of the two electrically insulating diamond layers locally open, allowing access to the electrode and to the area defining an electrical contact for the electrode; - a back face with the other of the two electrically insulating diamond layers, the first layer, the electrode, and the second layer each have thicknesses of less than one micrometer, preferably 500 nm, the electrically conductive layer has a thickness of less than 3 μm, the total thickness and geometry of the flexible implant being adapted so that the flexible implant conforms to the surface of the organ of interest, the total thickness of the flexible implant being less than 20 μm so as to provide flexibility. - at least one outer layer of biocompatible polymer, - a first layer of electrically insulating diamond, - at least one electrode of electrically conductive doped diamond in contact with the first layer of electrically insulating diamond, located at a first opening, - an electrically conductive layer of metal or electrically conductive doped diamond, in contact with: - the electrode, and - the first layer, - the electrode, and - the first layer, - a second layer of electrically insulating diamond at least in contact with the electrically conductive layer and a remaining part of the first layer, arranged so that: - an electrically insulating diamond/electrically conductive doped diamond seal is made at the electrode by epitaxial growth; - the electrically conductive layer is encapsulated by: • the electrode, the first layer and the second layer at the electrode, and • the first layer, and the second layer, over its entire remaining surface, except for an area located at a second opening defining an electrical contact by electrode for connecting the flexible implant via the electrically conductive layer to an electronic component to control the electrical coupling between the electrode and the nerve structure, the flexible implant with two faces: - a front face having one of the two electrically insulating diamond layers locally open, allowing access to the electrode and to the area defining an electrical contact for the electrode; - a back face with the other of the two electrically insulating diamond layers, - an electrically insulating diamond/electrically conductive doped diamond seal is made at the electrode by epitaxial growth; - the electrically conductive layer is encapsulated by: • the electrode, the first layer and the second layer at the electrode, and • the first layer, and the second layer, over its entire remaining surface, except for an area located at a second opening defining an electrical contact by electrode for connecting the flexible implant via the electrically conductive layer to an electronic component to control the electrical coupling between the electrode and the nerve structure, • the electrode, the first layer and the second layer at the electrode, and • the first layer, and the second layer, over its entire remaining surface, except for an area located at a second opening defining an electrical contact by electrode for connecting the flexible implant via the electrically conductive layer to an electronic component to control the electrical coupling between the electrode and the nerve structure, - a front face having one of the two electrically insulating diamond layers locally open, allowing access to the electrode and to the area defining an electrical contact for the electrode; - a back face with the other of the two electrically insulating diamond layers,