Il a fait ses affaires dans les vins = He made his money in the wine trade.
J’en fais mon affaire = I will take the responsibility of the matter; I will see to it; I will take it in hand.
Vous avez fait là une belle affaire (ironic.) = You have made a pretty mess of it.
Une affaire de rien = A mere nothing, a trifle.
Il est hors d’affaire = He is out of danger.
Être au dessous de ses affaires, être au dessus de ses affaires (ironic.) = To be unable to meet one’s liabilities, to be unsuccessful.
Quelle affaire! En voilà une affaire! (ironic.) = What a to-do! What a row about nothing!
La belle affaire! = Is that all? (i.e. it is not so difficult or important as you seem to think).
Il n’y a point de petites affaires = Every trifle is of importance.