Dr. Giraud is a French scientist, specializing in liquid Tiberium. He is employed by G-Tech and works in the Chilean Blue Zone.
Giraud was responsible for analysing recovered Nod research data on liquid Tiberium and advising General Jack Granger on how to deal with this threat. As such, Kane considered him a threat to his plans, but realized that his knowledge of Tiberium would be helpful.
As a result, Kane ordered the Nod AI LEGION to raid his laboratory in the Chilean Blue Zone and capture him before he informs GDI acting Director Redmond Boyle of Kane's intentions with liquid Tiberium. Using the Black Hand, LEGION attacks the laboratory and takes Giraud into custody. Despite repeated GDI attempts to shoot down the transport carrying him, Giraud was evacuated and disappeared from GDI's sight.
Perhaps his loyalties weren't as strong to GDI as initially thought, with the attempted shooting down of his transport certainly not helping. Giraud immediately developed the Tiberium Vein Detonation for Nod, and his continuing research into Tiberium contributed to the development of the portable Tiberium sprayer used by the Tiberium trooper.