Process for fabricating a multilayer optical filter within an integrated circuit, the integrated circuit comprising a substantially planar substrate, an interconnect portion (ITCI, ITCS) and an optical portion into which layers of the interconnect portion extend, the optical portion comprising said optical filter (FL1, FL2), the process comprising the formation of a photosensitive zone in the substrate, characterized in that the fabrication of the optical filter comprises an operation of forming a first filter portion within the optical portion facing the photosensitive zone, and a first distance away from the substrate, and an operation of forming a second filter portion facing the first filter portion and the photosensitive zone, a second distance away from the substrate, which second distance is greater than the first distance, and - an operation of forming a lower region (ITCI) of the interconnect portion (ITCI, ITCS) and the optical portion between the substrate and the first distance away from the substrate, and - an operation of forming a lower metal optical filter layer (ELMI), facing a portion of the lower region of the optical portion and the photosensitive zone, a third distance away from the substrate, which third distance is between the first distance and the second distance, the operation of forming the second filter portion comprising: - an operation of forming an upper region (ITCS) of the interconnect portion (ITCI, ITCS) between the lower region of the interconnect portion (ICTI) and a fourth distance away from the substrate, which fourth distance is greater than the second distance, facing the lower metal optical filter layer (ELMI) and the lower interconnect region, and - an operation of forming an upper metal optical filter layer (ELMS) facing the optical portion and the lower metal optical filter layer (ELMI), the second distance away from the substrate, - the two filter portions (FL1, FL2) being separated by at least some of the layers of the interconnect portion extending into the optical portion, the thicknesses of said layers of the interconnect portion extending into the optical portion being chosen so as to optimize the overall interference in said optical filter (FL1, FL2). - an operation of forming a lower region (ITCI) of the interconnect portion (ITCI, ITCS) and the optical portion between the substrate and the first distance away from the substrate, and - an operation of forming a lower metal optical filter layer (ELMI), facing a portion of the lower region of the optical portion and the photosensitive zone, a third distance away from the substrate, which third distance is between the first distance and the second distance, - an operation of forming an upper region (ITCS) of the interconnect portion (ITCI, ITCS) between the lower region of the interconnect portion (ICTI) and a fourth distance away from the substrate, which fourth distance is greater than the second distance, facing the lower metal optical filter layer (ELMI) and the lower interconnect region, and - an operation of forming an upper metal optical filter layer (ELMS) facing the optical portion and the lower metal optical filter layer (ELMI), the second distance away from the substrate, - the two filter portions (FL1, FL2) being separated by at least some of the layers of the interconnect portion extending into the optical portion, the thicknesses of said layers of the interconnect portion extending into the optical portion being chosen so as to optimize the overall interference in said optical filter (FL1, FL2).