She did not magically appear at Sorbonne and started studying. First she worked very hard, exhausted all the possibilities for studying (and then she even did more than allowed) in russian occupied Poland, then at the age 24 she was able to enter Sorbonne. It would be nice to honor all her history.

And during the years she worked supporting her sister she first learned chemistry from a chemist of the beetroot sugar factory, then took a semi-legal chemistry laboratory course in Warsaw (russian authorities banned such education for Poles in occupied Poland).

Poland didn't even exist on the map for most of her life. She had to leave to get educated.
Before that she had to work as a tutor and governess in rural areas for over 5 years supporting her older sister Bronisława studying in Paris until her sister graduated and could support Maria's studies.