OLd Castle in France perhaps?
Not France.
First hint: It's on the same latitude as Italy.
Slovenia, Croatia or Serbia for starters?
There are 21 regions in Croatia. Is it inland or near the coast?
Is the building some sort of a castle?
Yes, ehBeth, it's east of Zagreb. .
Just a guess, C.I. because I cannot find much on the map of Croatia, but is it Trakoscan castle?
Not Trakoscan caastle.
Second hint: We visited this castle during the Danube-Balkan cruise.
C.I., honey. Can you give us a more concrete hint?