Jean Baptiste Perrin (1870–1942)

Jean Baptiste Perrin (1870–1942) was a French physicist known for his work in the field of atomic physics. He is best recognized for his research on the nature of matter and his contributions to the experimental validation of the atomic theory. Perrin conducted experiments that provided evidence for the existence of atoms, particularly through studies of Brownian motion, which is the random movement of particles suspended in a fluid.

This seems like a cool dude. Besides a hardcore scientist, he also made many important contributions to the French education and research system.