'[Marie Noëlle on Karolina Gruszka] There was a lot of interest in the lead role of Marie Curie, but I couldn’t find any actresses who really convinced me. So I started to look for the leading role in Poland by myself and began to collect a lot of photos. Among them was a picture of Karolina that grabbed my attention. When we met, I knew that I had found my Marie Curie. And she could even speak French.'