Il n’y a pas de sots métiers, il n’y a que de sottes gens = People may be petty, but work never is.
Sou
Il a fait de cent sous quatre livres, et de quatre livres rien = He has brought his noble to ninepence, and his ninepence to nothing.
[Livre here has nothing to do with our English pound sterling. It is practically the equivalent of the modern franc. Hence the proverb means: He reduced 100 sous to 80 sous.]
Une affaire de deux sous = A twopenny-halfpenny affair.
Cela vaut mille francs comme un sou = It is worth £40 if it is worth a penny.
Souche
C’est une vraie souche = He is a regular log.
Faire souche = To found a family.
Soufflet