French authorities Tuesday cleared hundreds of migrants from two camps, one under a subway bridge in Paris and the other in the northern port of Calais.

The raids on the grotty, makeshift settlements come as European countries debate what to do about the tens of thousands of migrants crossing the Mediterranean from North Africa, many fleeing conflict and poverty in countries like Libya and Eritrea.

Police launched a dawn raid on a camp in northern Paris where more than 350 refugees, most of them from Sudan, but also from Eritrea, Somalia and Egypt have been living.

The camp, under raised metro tracks in a working-class area of the French capital, sprang up in 2014 but has since swelled as migrants cross the Mediterranean in ever increasing numbers and make their way north.

Authorities had put up signs over the weekend ordering the migrants to leave the camp within 48 hours and early on Tuesday morning police surrounded the site and blocked nearby traffic.

The refugees, most of them men, but also including several families, boarded nearby buses to be taken to various shelters in the greater Paris area.

"We're worried. We've been told they will be put up for several days but we don't know what that means, especially as some of them are here illegally," said Christiane, a local bystander.

The camp was broken up calmly while a handful of demonstrators shouted "solidarity with the migrants."

Health minister Marisol Touraine said the eviction took place for sanitary reasons.

"Camps are places that are always risky in terms of epidemics and health ... first and foremost for the people who live there. So the breaking-up of the camp is a response to a ... health need," she told French radio.

"We need to make sure that all of them are quickly rehoused and in good conditions," she added.

- 'Everyone ran off' -

Meanwhile, some 300 kilometers (200 miles) to the north, police evicted around 140 migrants from two makeshifts camps in Calais -- again without violent resistance.

One of the camps was very close to the Channel Tunnel, through which migrants seek to reach Britain.

"There was no official information," said Cecile Bossy from the charity group Medecins du Monde.

"When the authorities arrived, everyone ran off. The police asked them to take their stuff and leave," she said.

Agence France Presse reporters in Calais saw a scene of general confusion with some migrants drifting off in the direction of the city center.

"What's happening?" asked one baffled man from Sudan, who had been in Calais for three days after travelling through Egypt and Italy.

Tensions in the Calais camps have led to sporadic outbreaks of violence.

On Monday morning, a brawl broke out between Sudanese and Eritrean migrants, resulting in 24 injuries, 14 of which required hospital treatment.

Around 2,500 migrants, mostly from Sudan, Eritrea and Syria, live in the makeshift tent village in Calais known as "the jungle".

So far this year, more than 40,000 migrants have arrived on Italian shores and some 1,770 have perished on the hazardous journey.

On Wednesday, the European Commission asked member states to admit 20,000 Syrian refugees from outside Europe and process another 40,000 asylum seekers from Syria and Eritrea landing in Italy and Greece.

But France and Germany immediately hit back at the plan, saying it lacked sufficient "balance."