This old movie (1968) was filmed somewhere in the Castalli Roma. Does anyone know which town? The scenery is wonderful.

According to www.imdb.com, the movie was filmed entirely at Cinecitta, the humongous film studio near Rome:

http://www.imdb.com/title/tt0062767/locations

Does the movie title really mix up the languages and genders like that to be funny, or is that just a mistake? I never heard of this movie (or of "Buona Sera, Mrs. Campbell," if that's the real title).

sera= evening in Italian (feminine noun)

bueno= good in Spanish (masculine form of the adjective)

buona= good in Italian (feminine form of the adjective)

I just automatically assumed that it was written in (correct) Italian, i.e. "Buona Sera, Mrs. Campbell" and that's how it came up on IMDb.

Mea Culpa, cmt - you are right. It should have been "Buona Sera, Mrs. Campbell".
It is a "real" movie - and the back of the box says, "Set in a picturesque Italian village, Mrs. Campbell was filmed in its entirety in the Castelli Romani countryside just south of Rome."
So much for truth in advertising! I'll be in that area in May and was hoping I could actually visit that mythical village. Ah well.

Brahmama: Don't feel badly. Any movie, made anywhere, even on location, does weird and wonderful things with the locations.

Films made where I live will show the entrance to one building, and when the character walks through the door, the interior of another.