The Belgian architect who designed the Hôtel Tassel was Victor Horta.
Horta designed the Brussels townhouse for the scientist and professor Émile Tassel. Construction began in 1892 and the building was completed in 1893, making it one of the earliest major examples of architectural Art Nouveau. Rather than simply applying surface decoration, Horta integrated structure, circulation, materials, and ornament into a unified design.
The house uses iron, glass, stone, stained glass, mosaic, and wood around an open central stairway. A glass-covered connecting section acts as a light shaft, bringing daylight into the interior. Horta repeated curling, plant-inspired lines across the railings, floor tiles, doors, skylights, and wall decoration, creating the continuous “whiplash” effect associated with Belgian Art Nouveau.
Paul Hankar’s house was built at roughly the same time, so Hankar is sometimes mentioned in discussions of early Belgian Art Nouveau. However, the Hôtel Tassel itself is firmly attributed to Horta. In 2000 it became part of the UNESCO-listed Major Town Houses of Victor Horta in Brussels.