The shade is a Koloman Moser design for Bakalowits circa 1901. The shade is a Loetz Phänomen Genre 85/3839 decor. It reminds one of inverted waves and bubbles with warm gold and maroon tones interrupted by floating iridescent oil spots.
The grotesque Art Nouveau base is likely French by its hallmarks, and of the same period as the lamp. The hallmarks are shown in the photos. I have not be able to identify them. Overall height is 15" tall. The lamp is fully wired and is in excellent working condition.