E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
The dyeing of beards is mentioned by Strabo, and Bottom the Weaver satirises the custom when he undertakes to play Pyramus, and asks, what beard were I best to play it in?
I will discharge it in either your straw-colour beard, your orange-tawny beard, your purple-in-grain beard, or your French-crown-colour beard (your perfect yellow).Shakespeare: Midsummer Nights Dream, i. 2.
The French couronne = twenty-five francs, was a gold piece, and therefore the French-crown colour was a golden yellow; but the word French-crown also means baldness brought on by licentiousness. Hence the retort some of your French-crowns have no hair at all.