My mother, who was of french descent, used to make brioche. We would slather it in butter and eat it for breakfast with coffee. It was slightly sweet but I would still consider it in the bread family. I've never heard the interpretation of which you refer.
With Marie Antoinette’s comments “let them eat cake”. I have considered her interpretation to mean sewage sludge referred to at the time and sold to farmers as the kind of “cake” she meant. Accurate or not , my opinion only......:o)
http://www.straightdope.com/columns/read/550/did-marie-antoinette-really-say-let-them-eat-cake
Stay safe !
Cake to Ms. Antoinette was actually the burned part of the bread scraped off the bottom. Not nearly as nice as it sounds.