An assembly (1), in particular for an electrochemical sensor, comprises a functional body (2), which has a first material, wherein the surface of said functional body is at least partially covered using a plastic protective body (10), wherein at least one free section of said surface of said functional body (2) is not covered using a plastic protective body, and wherein said free section is delimited by at least one peripheral boundary line, which is closed per se, and at which said plastic protective body presses against said functional body, wherein an elastic sealing ring (4) presses against said surface of said functional body to form a seal in said plastic protective body at a distance to said boundary line, in order to seal the functional body (2) against a gap possibly occurring from the boundary line between the plastic protective body (10) and the functional body (2).