Lluís Domènech i Montaner (1849-1923), the great Art Noveau architect, continued the work on the Palau Montaner when, due to disagreements with the property, Josep Domènech i Estapà, the building's first architect, left them.

Despite the creative freedom the publisher Ramon Montaner i Vila, owner of the building, granted to Domènech i Montaner to build his family mansion, he decided to continue the work following  the box built by his predecessor , introducing ornamental elements and expanding the eaves planned to attenuate the severity of the lines and giving it character.

Lluís Domènech i Montaner, the publisher's nephew, had built the headquarters of the Montaner y Simón publishing house for his uncle and the publisher’s partner, Francesc Simon, on neighbouring Aragó Street. He had also been in charge of the design and management of several projects at the publishing house.

At the Palau Montaner, he enriches the exterior of the third floor with a glazed ceramic serial representation of Pre-Raphaelite figures, attributed to Alexandre de Riquer, on the arts and publishing, which balances the proportions of the facades.

Inside, Domènech i Montaner drew a wide hall with an imperial stone staircase with sculptural floral and zoomorphic elements. At the top he places a large mosaic glass skylight that illuminates the entrance with zenithal  light.

Domènech i Montaner was already surrounded by a team of the best craftsmen of the applied arts of that  time: with the mosaics by Lluís Bru, the sculptures by Eusebi Arnau, the woodwork and fabrics by  Gaspar Homar, the forge by Francesc Tiestos and the stained glass by Antoni Rigalt.