President Emmanuel Macron is seeking to centralise France's response to an influx of migrants in recent years as part of a new immigration bill being debated in parliament this week.
A migrant camp, mainly home to Afghans, has been spreading along the Canal Saint-Martin in recent months, and has now swelled to some 800 people.
Another 1,500 people, mostly Eritreans and Sudanese, have converged under an overpass on the Canal St Denis further to the north.
And the arrival of warmer weather could quickly swell their ranks, as seen at previous camps that have been dismantled in the capital in recent years.
“If nothing is done, in two weeks there will be 3,000,” Hidalgo told AFP, adding that she had asked the central government to find shelter but had so
far “not had a response”.
The greater Paris region currently has room to shelter just 750 migrants, many of whom hope for refugee status but may be facing expulsion under Macron's tougher approach.
Some have arrived in Paris from the northern port of Calais, where migrants have flocked for years hoping to stow away on trucks to Britain.
Officials in the area have deployed a heavy police presence to ensure that no more camps like the huge “Jungle” site that was razed in 2016 are set up.
The Local spoke to migrants at the Canal Saint Martin at Christmas time. Many were teenagers and had imagined something very different when they had imagined France.
“Teachers in school taught us about France and what a wonderful place it was,” said Khater, who said he was 15 years old, as he stood by the dozens of tents strung along the banks of the Canal Saint-Martin that now serve as home for hundreds of migrants.
On Wednesday, UN human rights experts deplored an “inhumane situation” in Calais and elsewhere in northern France, urging the government to provide
water and emergency shelters.
“We are concerned about increasingly regressive migration policies and the inhumane and substandard conditions suffered by migrants,” the UN's special
rapporteur on migrant rights, Felipe Gonzalez Morales, said in a statement from Geneva.
The government's draft law criminalises illegal border crossings and speeds up procedures to deport economic migrants, while offering faster asylum
But several NGOs and other critics say the new laws will lead to thousands of deportations, and the government has already abandoned a proposal to deport
failed asylum-seekers to third countries deemed “safe”.
France received a record 100,000 asylum applications last year and offered refugee status to around 30,000 people, official figures show. Forced
expulsions numbered 14,900.
“We're lying to the French by saying this is a temporary crisis that we'll fix with an immigration law,” Hidalgo said.
“Let's be practical: Find shelter for the people sleeping in the camps, and then we can look at their situations,” she said.