Although there are examples in Chaucer and Shakespeare of what we would now call Franglais, the word itself first appeared (I believe) in a humorous column written by Miles Kington in Punch magazine, beginning in the late 1970s. The column spawned a series of books, beginning with Let's Parlez Franglais! (1982).
In France the word has a much more pejorative implication, expressing a resentment of the use of words like le weekend and le parking.
© Haydn Thompson 2017