Many a one is good because he can do no mischief.
More French Proverbs:
To be willing is to be able.French
The villain that becomes rich knows neither friends nor family.
French
Everyone according to their talent and every talent according to its work.
French
Who blows his nose too hard makes it bleed.
French
A courtier should be without feeling and without honour.
French
Follow the river and you will reach the sea.
French