Are those frescoes real? Staged?

They're staged, of course, painted for the film. You wouldn't expect them to sacrifice real old frescoes, would you? :)

Regards, Rosabel

In Fellini EVERYTHING is staged: even the street with the open restaurants and the passing streetcar is staged in Cinecittà

I think this question really goes to the heart of the film. Fellini shows us a great city that exists both in its own past and in the present. In brief, yes the frescoes must have been staged, as their immediate self-destruction makes clear -- were they truly discovered accidentally by a subway-construction crew, there would have been no time for anyone to bring in a film crew to document them. So the fact that the modern (subway construction) and the ancient (frescoes) come into conflict, even unintentionally, is a staged and pre-planned part of the film's vision. Same thing is reinforced in the shots of rush-hour traffic stalled in passing ancient ruins. Rome, for Fellini, is a city still alive, and today's present will become tomorrow's past.

It's a fine line between clever and stupid.