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 Night's 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.”
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894