Actually, the full phrase is " la plume de ma tante est sur le bureau de mon oncle"(The pen of my aunt is on the desk of my uncle".)given as a sentence in French, as a demonstration of making gendered articles agree with gendered nouns. That is, the pen (considered as being female) and owned by a female, keeps on being female, despite being on the male desk of a male. That the article is supposed to agree with the object, not the subject, is demonstrated by a second phrase "la plume de mon uncle est sur la bureau de ma tante". (There is no easy genitive form in French, instead, the words, "de", "du" (de+le), and "des" are used.) That it's rather an awkward and formal sentence, contrasting the feminine-sounding "plume" with the boxy, male sounding "bureau", with a bit of a ring to it helps to firmly cement this sentence in mind, often long after any other phrases in French are lost to time and memory.

That having been said, I can also say that the introduction of this phrase in English teaching of French, comes at a time when writing was in a state of change in France.

Instead of using quill pens, the Napoleonic Republican used steel, and a chemical ink, violet in color, which had its own political meaning: violets were the favorite flower of the new order, displacing the Bourbon Lily. To use a steel pen, no matter how stiff and difficult it may be, was to favor the Revolution, to use the soft quill and lampblack and oakgall ink of the previous era, was to support l'ancien regime. Napoleonic pens were used in government and State-run schools in France up till the 1950's.

I can only state what I know. Still available from J. Herbin, they're a bearbugger with which to write.