We drove to Arnage at about 02.30 during the race and then moved onto Mulsanne at about 04.30, with no problems.
No one asked for a parking ticket or €8.
I suspect the ticket / payment issue comes into play during what the ACO regard as the peak hours (i.e. upto midnight).
I flet that numbers in both areas were down on last year, at the times we visited.
In fact, it felt like the total attendance was less than last year. Even towards the end of the race when a home when was a certainty, the terraces opposite the pits had ample space.