The equation: Both France and Australia must win. That is definite.
To be safe, either France or Australia must win by two goals.
If not safe (eg win only by 1 goal in each match) Australia must have more goals scored or less yellow/red cards or disciplinary offences than Denmark.
In a crazy scenario we may need to draw lots.
I don't like our chances because Denmark and France are likely to collude for the draw. (Maybe not)
Furthermore France have drawn 0-0 in all their final group games at 2014 WC and 2016 Euro when they were already through and rested several players. They will do the same here and rest 6 players I think...
Maybe a 10% chance.
Why am I thinking of Saudi Arabia v Japan?