Pig meat has traditionally been a staple food; this is illustrated by this French saying:

Dans le cochon tout est bon,
De la queue jusqu’au menton.
     translation:
In the pig all is good,
From the tail to the chin.

However, in French as in English, many pig idioms are derogatory; for example:

– avoir un caractère de cochon (= to have a pig’s temper): to be bad-tempered

– manger comme un cochon: to eat like a pig

– écrire comme un cochon (= to write like a pig): to have a bad handwriting

– c’est un travail de cochon ! (= that’s a pig’s work!): that’s shoddy work!

– quel temps de cochon ! (= what a pig’s weather!): what a filthy weather!

– un cochon n’y retrouverait pas ses petits (= a pig would not find its piglets in there): it’s like a pigsty in there, it’s a real mess in there.

– des perles (more commonly de la confiture) pour les cochons (= pearls (or jam) for the pigs): like the English phrase to cast pearls before swine, it means that it is foolish to offer something that is helpful or valuable to someone who does not appreciate or understand it, or who will seek to destroy it. It is a reference to the Sermon on the Mount, recorded in the gospel of Matthew, 7:6:

(King James Version – 1611):
Giue not that which is holy vnto the dogges, neither cast yee your pearles before swine: lest they trample them vnder their feet, and turne againe and rent you.

The word cochon also conveys the idea of excessive sexual drive; for example, un vieux cochon (= an old pig) means a dirty old man. And, according to the proverb, tout homme a dans son cœur un cochon qui sommeille (= every man has in his heart a sleeping pig), there’s a bit of the animal in every man. Likewise, the nouns cochonnerie and cochonceté are often used in the sense of obscenity.

The word cochon also refers to familiarity. The exclamation Eh bien, mon cochon ! (= Well, my pig!) is the equivalent of You old devil!. One would say on n’a pas gardé les cochons ensemble (= we have not looked after pigs together) to react to someone who is overfamiliar; it can translate as you’ve got a nerve!, we hardly know each other.

And the phrase copains comme cochons (= mates like pigs) means (as) thick as thieves. This expression is first recorded in Le Roman bourgeois (1666), by the French author and lexicographer Antoine Furetière (1619-88):

Ils se trouvent à la fin camarades comme cochons. (They find themselves at the end comrades like ‘cochons’.)

The expression du lard ou du cochon (= bacon or pig meat) is peculiar, as it consists of two words referring to the same thing. Se demander si c’est du lard ou du cochon (= to wonder whether it is bacon or pig meat) means to wonder what something is about. For example, on ne sait jamais si c’est du lard ou du cochon avec lui (= one never knows whether it is bacon or pig meat with him) means one never knows where one is with him.

The phrase cochon qui s’en dédit ! (= the one who goes back on his/her word is a pig!) is used when striking a deal; it can translate as let’s shake hands on it, or cross my heart and hope to die.

Finally, si les petits cochons ne le/la mangent pas (= if the piglets don’t eat him/her) means if nothing gets in his/her way; for example, il ira loin, si les petits cochons ne le mangent pas translates as he’ll go far, if nothing gets in his way.