In 1887, the Barcelona City Council called a tender to renovate the Casa de la Ciutat as a residence for the royal family during the Universal Exhibition of 1888. Domènech i Montaner carried it out. The Casa de la Ciutat building, of medieval origin, had arrived at the beginning of the 19th century in a deplorable state of repair. Various restoration and extension works carried out around 1820 had improved it somewhat. But the royal family had to be housed. At first the competition was declared void, and Mayor Rius i Taulet entrusted the project to Antoni Gaudí. He even presented some plans, but the Government Commission urgently commissioned Domènech i Montaner to design the project, and his went ahead. His proposal was not carried out in its entirety, and in many cases it was simplified to speed up construction, which took little more than two months. Domènech's contributions were of a constructive and distributive nature, and the restoration and reinterpretation of the interior decoration. A new monumental staircase was built to dignify access to the first floor and the space between the courtyard and the Saló de Cent was redistributed. The mayor's office and other municipal offices were relocated to accommodate the royal family. Domènech also recovered the old Gothic access gallery to the hall by demolishing all the partitions that covered the arcades and recovering the geometry of the buttresses, which had been heavily modified and had caused serious structural damage. The medieval polychromy of the coffered ceiling was recovered, windows were uncovered and new stained glass windows were installed, cabinetwork, upholstery and flooring work were carried out and skylights were created to provide natural lighting and electric lamps. Once the royal visit was over, Domènech asked for the decorative works and structural reinforcement to be completed, but they were not carried out. The modifications that were made to these spaces over the years made a large part of Domènech's work disappear.

The Barcelona City Council complex is made up of three buildings. The ancient building, six centuries old, is a veritable treatise on the history of the city and the different architectural styles, from Gothic to modernism. The so-called "new" building was built on the international exhibition of 1928. The so-called "newest" building, designed in 1958, is a controversial high-rise building in the heart of the city's historic centre. The administrative decentralisation of the town hall has made the approach of a general remodeling possible. The urban objectives set out are to recover the historical dimension of Sant Miquel Square. The dignification of this abused space is sought through the following actions: the search for a new location for the car park in the square, the display of the Roman ruins underground and the reduction of the height of the brand-new building. The aim is to establish an urban autonomy between the three buildings and a skyline more suitable to the plot of Ciutat Vella. The functional objectives of the set are to enhance the permeability of the buildings for urban use. Access to all three buildings is provided from a single entrance hall. It is proposed to improve the connection between the three buildings, making the labyrinthine character and the architectural barriers disappear. Finally, a location has been sought for the new meeting room: more comfortable, well equipped, and with more capacity. The architectural proposals proposed in the remodeling start from a general sponging of the buildings, from the elimination of additions and corners produced by the indiscriminate accumulation of uses. In the historic building, we want to highlight the uniqueness of the Saló de Cent, making the whole complex more understandable. The new vertical circulation of the old building allows the understanding of all the floors of the building and, at the same time, works as an access door to the new building, starting from the new axis (Sant Jaume Square), the old building and the new building. The recovery of the functionality and urbanity of the entrance of new and brand-new buildings is achieved through the appearance of a large access loggia for outdoor activities.