The first-ever centre-right primary in France was an expensive business, costing eight million euros.
But, thanks to a charge of two euros for casting a vote, the organisers have made a tidy profit.
Costs included a 750,000-euro payment to the post office, whose bank handled the counting and transport of the money collected.
The organisers say negotiations were long and hard and ended with the post office accepting an eight percent cut of the take.
But it also accepted a ceiling of 750,000 euros, which seriously reduced its cut.
They also have to repay a five-million-euro loan to the largest party involved in the primary, the Republicans.
Income was a healthy 16 million euros, from the pockets of about four million people voting in each of two rounds.
Some of them were left-wingers who were inspired to vote by opinion polls predicting next year's showdown will be between the mainstream right candidate and the far right's Marine Le Pen.
They paid up to try to stop former president Nicolas Sarkozy in the first round and Fillon in the second, unsuccessfully in the latter case.
After the costs are subtracted there is a balance of eight million euros, which will go to Fillon's election campaign, which has already benefited from the TV debates and other publicity during the primaries.