The Palazzaccio or Casa dell'Abate (Abbot's House) is the oldest building in San Giovanni, with its particular high portico made with oak columns, attic and small rectangular windows.

The building dates back to the 13th-14th centuries and was used to store tithes for the Abbey of Nonantola.

The palace is part of the real estate of the Consorzio dei partecipanti (Consortium of participants) of San Giovanni in Persiceto, as well as the Casa Grande in the nearby hamlet of San Matteo della Decima. The Palazzaccio can be seen only from outside, while the building in San Matteo has been restored and converted to homes, offices and is available for cerimonies.