Finally, we have discovered the name of the "white cat peeking by the window". She is Sniezka (or Snieska) which I believe means "show" in Polish or something. The owner noted we were taking picture of her and became a friend. Now, he brings Snieska to visit my parents, regularly. So, they can pet and stroke her.
Here, Snieska is visiting my parent's house in Savona (Italy).