Chef de brigade was a military rank, equivalent to colonel, in the French Revolutionary army, in command of a demi-brigade. Both that unit (replacing a regiment) and that rank (replacing the rank of mestre de camp) were created at the same time, in 1793. The two designations disappeared just before the institution of the French Empire, in 1803, with the old designations restored.
The original article can be found at Chef de brigade and the edit history here.