Abstract:Henri III is, among French kings, one of the most concerned with the power of eloquence, especially with actio or body eloquence, trained by several treatises by humanists, in particular Rhetorique françoyse (1579-1580) dedicated to the king by Germain Forget. The originality of this treatise lies in its quotations taken from Robert Garnier’s contemporary theatre. His plays are in fact a school of eloquence and gestures for the king.