To manufacture coatings having functions to protect an inorganic supporting body and to prevent graffiti.

The coatings are produced by carrying out a first stage and a second stage. In the first stage, an organosiloxane having at least one triamino group, at least one Si-C-coupled fluoroalkyl group and at least one hydroxyl group and/or alkoxy group, or an agent containing the above organosiloxane or containing a mixture of the organosiloxane, or alkylalkoxysilane, or an agent containing at least one kind of organosiloxane having at least one amino group, at least one Si-C-coupled linear or branched or cyclic alkyl group and at least one hydroxyl group and/or alkoxy group is applied on the supporting body. In the second stage, the above organosiloxane or a compound containing the organosiloxane is applied to form another layer on the treated supporting body. If necessary, the second stage is repeated once or more.