Reader question: Why are there such wide variations in the number of people reported during protests?
On January 19, the CGT union claimed that 400,000 marched in Paris, while the prefecture said there were 80,000.
Such differences are a staple of any strike in France and partly reflect organisations’ aims.
For unions, for example, if they err on the higher side, a large figure will help bolster their demands.
They are also a result of the methods used to count attendees.
Organisers station people at various points to count the rows of protesters who walk past, before multiplying this by the average number of people in a row.
The police use a similar method, but claim to take more precautions.
Officers in elevated locations at two or more points along the march route use hand-held clicker counters to count each line of protesters, having calculated the number of people per line, the Interior Ministry said in response to a question from a senator.
“These measures are put in place in strategic zones, meaning ‘test’ stretches of road where the dimensions are known and they allow a working count of protesters, depending on the width of the road occupied, density, and the time taken to move through the zones,” the ministry said.
The different figures are averaged out, and then increased by 10% to take a margin of error into account.
The next day, they will use video footage from the protest to check if their estimation was correct.
In 2015, a report by independent experts commissioned by the Paris police said the police’s method was reliable.