The Roberval balance is a weighing scale presented to the French Academy of Sciences by the French mathematician Gilles Personne de Roberval in 1669.
Allez Frères began in 1803 as a quincaillerie (hardware store) run by François Victor Allez (b. 1773) and his brother Louis Charles Nicolas Allez (1763-1844) at 40 quai de la Mégisserie in the 1er arrondissement in Paris. 
Every market and household used those scale balance for centuries .
H.10 1/2 in x L.22 in  x  plate D. 9 in .
Good condition , I can be reach at the 310 994 6009 if you want more info , for shipping outside the US please contact me for pricing and condition .