In little over 30 minutes, as the last polling stations close at 8pm, French media will publish their estimates of the final result. They may vary by a percentage point or two, but are generally highly consistent.
Unlike the exit polls in many countries, in which people are asked how they voted as they leave the polling station, these estimates – in use and steadily perfected since 1965 – are based on a vote count.
Pollsters select about 200 early closing polling stations around the country – in rural areas, small towns and urban agglomerations – carefully chosen to be as representative as possible of the country as a whole.
As soon as those stations have closed at 7pm, and as their votes are being counted, a polling official records, for a sizeable sample of the ballots, the number of votes cast for each candidate.
Those numbers are then run through a sophisticated computer program that adjusts them for past results and assorted variables, and produces a national vote estimate. These are not the official result, but they are also not an exit poll.
They are also very accurate, usually to within a percentage point.
Over the course of the evening, as the interior ministry’s official count advances, it will give different numbers, but that is because the earliest final counts come from rural areas that traditionally favour the right.
Gradually, as bigger towns and cities start to declare, the official count and the pollsters’ 8pm vote estimate come into alignment.