There is of course no evidence that Marie Antoinette ever used the words ‘Let them eat cake’ or any variation on these words. It was originally attributed to ‘a great princess’ by Rousseau when Marie Antoinette was (a) 14 years old and (b) still living in Austria. It was attributed to her many years after her execution by people seeking to justify the overthrow of the monarchy.
In short, it was Fake News.