I disagree with the remarks in the Trivia section

OK, this title is translatable, but it helps to know some French. The first thing is to realize that the words "le fond de l'air" taken as a whole is idiomatic which means that even if you know the individual words, you're still not clear as to what the entire expresion means.

Here's the entry from the French dictionary, Le Petit Robert":

7¨ Fam. Le fond de l'air : ce qui semble être la température réelle, de base, indépendamment des accidents momentanés (vent, ensoleillement). Le fond de l'air est frais.

The above entry says that the expression "Le fond de l'air" refers to the actual temperature of air, independant of any such brief occurences as from wind gusts or sunbreaks.

So, according to the above, the title of this movie would translate as, "The Real Temperature is Red". This simple translation lacks the force of the original words since the original contains a variation or a play on words from an idiomatic expression.

Also at work in the original title is the use of the adjective "red" in a sense that goes beyond its normal sense, and that color red really brings up images of blood and the revolutionary flag.

The remarks in the Trivia section miss the point if you do a literal translation of the title which lieavs you looking for something in the air which cannot be since it has no substance, so the movement has no substance...

I suppose explains why other translations "Grin without a Cat" and "Base of the Air is Red" have been offered. The former is an attempt to capture the spirit of the original but declares the movement a pathetic failure, the latter simply a literal translation which makes no sense.

To say that the title of this movie suggests that the revolution was in the air but not on the ground is not an accurate statement that I would expect from anyone who knows French.

If Marker really wanted to name the film in a way that would say that the struggles of the left had been a failure, he might have used "black" instead of "red".