Toussaint-Henry-Joseph Fafchamps
Joseph Montigny further improved the weapon, completing the transportable 37-barrels Montigny mitrailleuse (also known as the "Fafschamps-Montigny mitrailleuse") in 1863. From 1859, Joseph Montigny proposed his design to Napoleon III, which led to the development of the French Reffye mitrailleuse, designed by Jean-Baptiste Verchère de Reffye with the collaboration of Montigny, and which was adopted by the French Army in 1865. The invention of Fafschamps thus became the basis of the "mitrailleuse", which was used by the French in the Franco-Prussian War of 1870. Initially kept under wraps as a secret weapon, it became widely used in battle by French artillery during the Franco-Prussian War (1870–71).
René Baillaud
He invented the "paraboloïde" a precursor of the radar. This instrument made it possible to establish the position of planes without having to see them, using only the sound they produced. The precision of the instrument was such, that it was used during the first world war by the French military, to reppel night attacks from German bombers by pointing searchlights at them. This furthermore represented a rare technological superioty for the French. After this remarkable start in the fields of acoustics, he nonetheless decided to abandon this field. The reason being that his professor's own instrument didn't get chosen by the French military, and René feared he would have no academic future in this field. He then turned chronometry.