Micromechanical functional assembly with a tribological coating

A micromechanical functional assembly comprising at least one first part formed by a first substrate topped by a first functional surface intended to enter into frictional contact with a second functional surface, said second functional surface belonging either to said first part or to at least one second part formed by a second substrate topped by said second functional surface, the second part constituting with said first part said functional assembly, wherein said functional assembly comprises the first functional surface and the second functional surface are formed by a first layer which is either integral with the first substrate and the second substrate or distinct from the first substrate and the second substrate, the first layer comprising ultrananocrystalline, nanocrystalline or microcrystalline diamond and being topped by a second layer including S and F atoms and wherein the second layer has an average thickness of between 2 and 50 nm.