Namep olygons according to underlying polygons

I have a set of polygons derived from topography and a set of polygons I use for validation purposes. Now, I would like to assign the IDs of each validation polygon to the according derived polygon on top. I think I need to use a cursor, but since I am absolutely new to Python, I'd be happy to hear if someone might have used a piece of code like this before and can give me a hint on how to write it.
Any advice is greatly appreciated!