Police say 1 million, organizers say 3 million. Such discrepancies are often the case when politics and passions are involved, but in the case of the French labor protests they appear particularly large. Why? Firstly, because the numbers marching - by either count - are so big that mistakes are easier to make. Police and union organizers both say counting becomes more difficult, even approximative, when demonstrations grow so large. For unions, the higher the number, the greater the pressure they can exert on France's government to withdraw its contested jobs law that would make firing young workers easier. Union members note that when the stakes and tensions with the government are lower, police and union estimates tend not to differ so much. Police insist that they have no interest in playing down the size of marches - although the numbers they give sometimes seem overly modest to outside observers. In practice, police and unions' counting methods are often not hugely different, yet unions routinely come up with figures two or three times the size of police ones. Police say they place counters at fixed points along a march route. The officers count the number of marchers per line, stretching from one side of the street to another, and multiply that by the number of lines that march past to get a total. Counting methods can differ from one union to another. The FSU, the main teachers' union and among those leading the job contract protests, says its officials also count by lines. For very large protests, police say they also calculate numbers using the surface area taken up by a march, sometimes using a helicopter. Some marches in Paris against the job contract have stretched over several kilometers (miles). Either way, both organizers and the government agree: marches against the job contract have been unusually large, even by the standards of protest-friendly France.