Police and city officials are evacuating at least 1,600 migrants from Afghanistan, Sudan, Eritrea and elsewhere who have been living on the streets of northern Paris for weeks.
Paris City Hall said two operations were carried out on Friday morning on a stretch of pavement underneath an elevated metro line not far from the Montmartre area.
One evacuation focused on about 80 women and children in the makeshift camp, while the other focused on the men, according to a statement from City Hall.
An official with the Paris regional administration said more than 1,000 people had been transported to temporary shelters by mid-morning, while authorities estimate about 1,600 to 1,800 migrants had been living at the site overall.
They are being driven to 74 sites around the Paris region where authorities will give them food and medical treatment and help those who are eligible apply for asylum.
The regional administration official said a minority of the migrants refused to be shuttled to temporary shelters, some because they want to try to get to Britain instead.
Paris authorities have carried out several similar operations this year in the same area, most recently a month ago, but it remains a magnet for migrants.
The city's mayor Anne Hidalgo said several dozen migrants arrive every day, and is planning a reception centre for them nearby.
France has come under criticism for its handling of Europe's migrant crisis, notably for allowing thousands of people to live in squalid conditions in a camp in the northern city of Calais.