Passatge de la Pau is the result of an urban planning intervention in the second half of the 19th century in the Gothic quarter of the Ciutat Vella district. The building complex forms a formal architectural unit whose aim is to achieve a large number of new dwellings on a small plot, while maintaining optimum conditions of habitability. Passatge de la Pau passes through the middle of this complex, maintaining the urban continuity of the roads, which is only altered in height, as parts of the building pass from one side of the passage to the other.

The building is made up of two main volumes on either side of the passageway. Three bridging bodies link the two volumes to form two open spaces without affecting the passage through the passageway. This curious typology of spaces is emphasised by the fact that at the ends, at the entrance and exit, the raised volumes are integrated into the street façade in such a way that access to the passageway is limited to simple doorways. This does not prevent vehicles from passing through the passageway.

The buildings have a ground floor and four storeys. The raised bodies are three storeys high and rise from the second storey, their cornices being aligned with the rest of the main volumes around their perimeter. Of these two volumes, the east-facing one is wider, as it has six bays, while the other is much narrower, with only two. The buildings will have access from inside the passageway, except for number 12, which has access from the outside. There is even an access from Carrer Josep Anselm Clavé and another from Carrer Sils.

Both building volumes are quite dense in terms of buildability, which is why they are perforated by a series of small courtyards that provide ventilation and also light in the secondary rooms that do not have a façade. Similarly, several stairwells articulate the entrances to the floors and connect them with the lobbies. The ground floor is entirely occupied by commercial premises and the lobbies.

As far as the façades are concerned, the most characteristic aspect is the strict formal and aesthetic unity of all the façades and the carefully studied geometric relationships that articulate them.

The most important façade is the one facing Carrer Josep Anselm Clavé. This is formed by a grid of openings – semicircular portals on the ground floor and balconies on the upper floors. This grid is broken by a double-height arched doorway that leads to the passageway. This architectural element is quite prominent as it has archivolts set on two pilasters of considerable dimensions. This arch is surrounded by an entablature crowned by a cornice with dentils. On the frieze there is a sign with metal letters indicating the name of the passageway in Spanish. The rest of the openings are of simple geometry and have more neoclassical mouldings, stone slab balconies and iron railings.

The façade of the north entrance on Carrer Sils also has a doorway and the architectural element that contains it is similar to the previous one, but with the particularity that it occupies the entire height of the building. Pilasters appear on both sides of the central balcony on each of the levels until reaching the cornice where it is transformed into a semicircular pediment with corbels and a central coat of arms. In this façade the openings are balconies only in the central element and the rest are windows.

The interior façades are of equal simplicity and compositional rigour. All the openings are balconies and also follow a homogeneous geometric grid formed by the axes of the balconies and small cornices that mark the floor slabs of the building. Special mention should be made of the balconies of the main balcony, which have a lintel with neoclassical plant decorations.

The roofs are flat with a roof terrace. The façades are finished off with cornices and sills in neoclassical forms. It is worth mentioning the false ceilings of the flying bodies, which are decorated with polychrome plaster decorations, except for the one at the southern end, which has disappeared, revealing the wooden beams and brick vaults.

An architectural element of note is a fixed but raised grille in the area of the soffit of the arch right at the starting line.

The materials of the façade are masonry clad in mortar with cut stone framing.