This one was taken in Piazza Cavour at the heart of modern and medieval Rimini. It was known as Piazza della Fontana until 1862, and Piazza del Comune earlier than that.
To the right side you can see the Palazzo dell'Arengo, a Malatesta fortified residence with nice brickwork in the insets of the Gothic arches and at the back, the Palazzo del Podestà, a neoclassical theater. In the centre of the square (at the front of the image) has stood the statue in bronze of Paul V erected in 1614, work of Nicoḷ Cordier and Sebastiano Sebastiani. Although you can't see in this photo, there's also a wonderful circular fountain built in 1543 by Giovanni Carrari da Bergamo, "Fontana della Pigna", which must have been superb for watering horses.
As curiosity, the Piazza Cavour, which along with Rimini’s other main square Piazza Tre Martiri, provided the model for the square featured in Amarcord. It is a well-known fact that Fellini always re-built 'his Rimini' elsewhere.