This is a sort of arcane joke on my part. The French sometimes mangle words imported into their language as badly as we do.
In this case they transformed English “beefsteak” into bifteck.
And of course it‘s an allusion to the line commonly attributed to Marie Antoinette when told that poor French people had no bread to eat: “Let them eat cake.”
In fact the story originated long before the French Revolution, when Marie Antoinette was just a little girl. Jean-Jacques Rousseau wrote in Book 6 of his Confessions:
Finally I recalled the stopgap solution of a great princess who was told that the peasants had no bread, and who responded: “Let them eat brioche.”
We of course translate brioche as "cake"—so there is another linguistic confusion involved.
Languages don’t get to rule on the use of words when they are adopted into other languages.
The French, for instance, use “shampooing” not as a verb, but as the noun naming the liquid stuff you pour out of a bottle.
And brassière, a word meaning “baby‘s vest” or “life jacket,” takes on quite a different meaning in English.