Production Designer is the above the line department head of the Art Department. Ausstattung is Art Direction for the movies, Bühnenbild is the same, but only for Theater and Szenenbild is Art Direction for TV. Set Decoration in German Movies is called: Innen-Requisite and the person who acquires the dressing materials is called Außenrequisite. Props can be both: Außen wie Innen-Requisite.
The Production Designer with the Art Department crew create the "look" of a film in consultation with the director and cameraman. Developes the style of the decor and architecture. This includes the selection of locations and the definition of characters by their environment (colors, materials, special furniture, etc.).
The Designer is the "visual" communicator between directing, cinematography, VFX (Visual Effects) and SFX (special effects). It is the designer's responsibility to control all departments involved in the look of the film to achieve a coherent picture.
During the shoot, the Innenrequisiteur (English on set decorator and prop master) responsible for the use of the correct props and the decorations on the set. Props on a US set are strictly items in the scene that are handled by the actors - e.g. gun or knife. A set dressing might be a burning candle or ashtray, this is not however a prop.
During production it is common for the actors to disturb set dressing or props, which must be replaced in their exact position for subsequent shots. If they are not precisely reset, there will be a lapse in continuity.