Some 1,700 Parisian volunteers and 300 officials carried out the census last Thursday night, going street by street counting the number of people huddled in sleeping bags in doorways or camped out in tents.
They also surveyed homeless people about their housing and health problems, collecting data that Socialist Mayor Anne Hidalgo hopes will allow authorities to design better policies to help those on the streets.
Deputy mayor Bruno Julliard, unveiling the results, warned that the figure of 2,952 people sleeping rough -- added to 672 in emergency winter shelters -- was a low estimate.
"Car parks were not taken into account and nor were the staircases of buildings, notably social housing," he said, pointing to places where people typically take shelter in the winter.
"We didn't open tents where several people may have been sleeping."
Cities such as Athens, Brussels and New York have also carried out official counts of their homeless in recent years.
President Emmanuel Macron had last July promised to end rough sleeping across France entirely by the end of 2017, and acknowledged last month that he had failed to meet that ambitious goal.
Visitors to Paris are often shocked by the poverty that exists in some parts of the capital, especially the omnipresent beggars on the metro and the migrants' tents perched along the Canal Saint-Martin.
The 3,000 figure is in line with previous estimates from homeless charities.
But homelessness has been at the centre of a political row in recent weeks after two members of Macron's party made comments seen as out of touch.
Urban affairs minister Julien Denormandie prompted an uproar late last month by asserting only 50 men were sleeping rough in the wider Paris region, earning him scorn from charities.
The figure turned out to refer to those who called an overstretched emergency hotline seeking shelter but were turned away.
And days later, Paris lawmaker Sylvain Maillard, a member of Macron's party, added fuel to the fire by insisting that some stay on the streets, even in the snow, "by choice".
Macron's centrist government has defended its policy on homelessness, stressing that it has opened 13,000 extra places in emergency winter shelters.
- with AFP