Edifici neogòtic de grans proporcions amb una nau central i dues laterals. Les estructures segueixen els elements propis del gòtic francès: planta de creu llatina, arc i volta d'ogiva, gran funcionalitat, existència de contraforts, campanar d'agulla i simplicitat decorativa. La façana principal té una porta amb timpà ogival decorat amb relleus i gablet amb pinacle superior. Al centre de la façana hi ha una gran rosassa calada. El coronament és a dues vessants i amb pinacles als extrems.

Located in the Eixample district, Casa Robert is in the northern corner of the block of houses bordered by Passeig de Gràcia, Rosselló Street, Rambla de Catalunya and Còrsega Street, off Diagonal Avenue. It is an isolated building in the middle of a garden that is public today. With a rectangular floor plan, the elevated structure of the building includes a semi-basement, ground floor, main floor, attic and walkable roof. The building has two entrances: one facing the rear garden and another (the main one) facing Passeig de Gràcia. This last access leads to a large lobby area that contains the staircase to the ground floor. Casa Robert is a neoclassical building with a cubic shape that shows three façades on the outside, all finished with stone extracted from the Montgrí Massif (where the owner came from and would end up holding the title of Count). Each façade has a different composition, although they share some main characteristics that unify them in terms of style. The large openings are always aligned in vertical axes and the semi-basement is included in a robust white stone base. The amphitheatre balconies on the ground floor have a flat arch shape, framed with lintels and uprights based on highly plasticised padded ashlars. These balconies, like those on the main floor, are enclosed by stone balustrades. A moulding decorated with a wave-based edging serves to separate the padded facings of the ground floor from the plain ashlar facings of the main floor. The main feature of the main floor is that the balconies, in this case crowned with moulded semi-circular arches, are flanked by delicate piles of flowery Ionic order that support an entablature worked with scroll-shaped corbels. On the cornice of this entablature rest the windows of the attic or second floor, austerely moulded. The balustrade that closes the roof rests on the Corinthian entablature of the attic. The façade facing the garden has a much more rigorous rhythm, with two lateral bodies flanking the central one, which stands out for its padded walls and for being crowned by a triangular pediment. This pediment houses, in relief, two pigeons among the vegetation holding a shield that, although today it is that of the Generalitat de Catalunya, originally showed the arms of Robert Robert. The main façade, facing Passeig de Gràcia, has a varied composition, playing with the rhythms of the opening axes. In addition, the two balconies at the ends of the main floor have a stone cantilever supported by two large corbels and closed by a cast iron railing. The southern end of this façade has a smaller terraced body that contains a large semi-circular arch framed by a portico of flowery Ionic semi-columns that support an entablature. The arch is enclosed by a monumental wrought iron grille with a pebble design, with gilded cast iron sconces and a golden shield of the Generalitat. This body forms the main access to the building, and inside it contains a monumental lobby that allowed the visitor to enter the house by car and park inside the garages located on the other side of the garden. This lobby is probably the richest one in the city and is set up as a spectacular colonnaded gallery based on groups of columns and flowery Ionic pilasters that support a barrel vault with lunettes of great stereotomical refinement. The colonnade on the left allows access to the caretaker's and porter's offices, while the colonnade on the right houses the main door of the house. It is crowned by a semi-circular arch topped with a powerful shield (now empty) richly framed with reliefs in the shape of an acanthus leaf, two rampant dogs and a helmet with the crown of the Marquis. This door allows access to the main staircase, inside a stone box decorated with flowery Ionic pilasters and oeil-de-boeuf framed with bows and laurel garlands. This staircase leads to the space that centralises the entire building: the main lobby on the ground floor. This grand space was conceived as an elevated courtyard covered by a skylight, the height of which also includes the main floor to which it gives access. This monumental cubic room finished in stone serves, at the same time, as a lobby, as a distributor on the ground floor, as a stairwell to the main floor and as an open space. Its stone walls are home to monumental doors with moulded lintels and jambs and oeil-de-boeuf with laurel wreaths. The corners of the room are rounded and its floor is completely covered with white marble, with decorative motifs in marble of other colours. At the bottom of this space is the staircase of the main floor, forming a sinuous marble line enclosed by a railing decorated with gilded bronze pebbles. All the rooms around the staircase have walls and ceilings covered with classically inspired mouldings that, unfortunately, have lost their original polychrome and gilded decoration.