personnage muet, man who doesn't count. Technically one who appears on the stage but does not speak.
cour prévôtale, provost court, or "court martial," "a criminal tribunal temporarily established, and judging without appeal" (Littré).
bord, party, side, or way of thinking. See also dictionary.
notre classe. This is a delightful touch. Montrichard, having been republican and bonapartist, now chooses to regard himself as one of the original aristocracy.