I would love to give a lavish explanation as to why I was allowed in the J/S, however, i guess it was just a mixture of luck and the fact that AF seem pretty lenient when it comes to that sort of thing.

Since that trip I've had the same thing happen to me on a flight CDG-BKK (only for them to find me a seat in economy! all out of luck on that trip) Nowadays all AF staff tickets are electronic and dont contain the scope of info on the party traveling that the old 'open' paper stand-by' used to. However because they are issued through a special online res system, they know for sure that you are AF staff (of one form or another!)