Protesters entered the site without causing damage and held banners calling for an end to the violence in Gaza.
Messages included “Stop the blood bath in Gaza” and “Stop Genocide”, urging an end to military trade deals and demanding immediate humanitarian access to the Gaza Strip.
The protest took place at the Acqua Paola fountain, known locally as "Fontanone", which featured in the opening scene of the Oscar-winning film The Great Beauty.
A wider demonstration involving opposition parties and civil society groups is planned for Saturday in Rome, calling for a ceasefire.
