Auberge d'Italie was originally designed by Gerolamo Cassar and is a two-storey palace built in 1574 as lodging for the Italian Knights. The upper floor was probably constructed in the late 17th century as part of Grandmaster Caraffa's remodelling project. The lower level is comprised of a mezzanine level characterised by square windows. The entrance portal onto Merchant's Street is decorated with Caraffa's effigy and includes an inscription and a bust of the same grandmaster. A cluster of marble trophies surrounds the bust. The auberge as it stands today, has undergone several changes and it is difficult to ascertain Girolomo Cassar's original structure.

In the centre of the auberge's courtyard is a triumphal arch erected above a well, having a large, pot-shaped well-head at the centre. Both front and rear of the arch are identical, consisting of two clusters of composite pilasters, within which is an arch supported on the imposts of two shorter doric pilasters. The entablature has a plain frieze, which on the rear at centre has the dates "1756" and "1862" carved above each other.

The arch is crowned by a curved broken pediment, with a central feature consisting of an elaborate niche with the statue of St Catherine on the rear and the coat-of-arms of grandmaster set in a trophy of arms at the front.

Mepa scheduled the Auberge d'Italie and the triumphal arch as Grade 1 national monuments as per Government Notice number 276/08 in the Government Gazette dated March 28, 2008.