A former member of the French Second Armored Division and Companion of the Liberation, François Jacob risked his life to defend the fundamental values of democracy and freedom. He was a brilliant scientist who spent his entire career at the Institut Pasteur and who inspired many researchers who followed in his tracks. François Jacob never missed an opportunity to demonstrate his commitment to the Institut Pasteur. On November 14, 2012, alongside the President of the Republic, he was delighted to be able to inaugurate the new building that bears his name. The obituary below was written by Michel Morange, a former pupil of François Jacob who works as a biologist and science historian.