S'en moquer comme de l'an quarante

Literally: To care about it as much as about the year forty

Example: “Les critiques ? Il s'en moque comme de l'an quarante.” — The critics? He doesn't give a hoot.

English equivalent: Not to give a hoot

Origin: Attested at the end of the 18th century, origin unknown, and the modern lexicographers do not agree. Six accounts circulate. The year 1040 as a predicted end of the world, being 1000 plus Christ's lifespan — except that he is normally said to have died at 33, and it is hard to see the joke waiting seven centuries to be made. The year 1740, for which calamities were forecast and nothing happened. Littré's reading: a royalist sneer at year 40 of the Republic, a year the republican calendar never came close to reaching. A sans-culotte joke about the age Louis XVI would have reached shortly after being shortened. A deformation of the very popular s'en moquer comme de l'Alcoran — the Koran, in the spelling of the day — which Alain Rey rejects for want of evidence and Claude Duneton defends. And the year 2440, from Louis-Sébastien Mercier's hugely popular pre-Revolutionary novel imagining a utopia that far off, which the sans-culottes are supposed to have found funny given their own arrangements. Duneton's version has the last two blending into each other.