France on Tuesday hailed the recapture by Syrian forces of the ancient city of Palmyra as "positive news" but stressed Damascus bore the main blame for the war in Syria.

A video of a police officer punching a teenager sparked fury in France on Friday, with high school pupils staging violent protests outside police stations in the capital.

The video shows two policemen holding up a 15-year-old boy while another violently punches him, on the sidelines of student protests Thursday against proposed labor reforms.

French Finance Minister Michel Sapin was heavily criticized on Wednesday after he accused Belgian authorities of "naivety" over the spread of Islamist extremism.

"I think there was a will, or a lack of will, on the part of some (Belgian) authorities... perhaps also a kind of naivety," Sapin said Tuesday, suggesting that they "thought that to encourage good integration, communities should be left to develop on their own."

French President Francois Hollande said Tuesday's attacks in Brussels that killed at about 35 people struck at "the whole of Europe".

"Through the attacks in Brussels, the whole of Europe has been hit," Hollande said in a statement, urging the continent to take "vital steps in the face of the seriousness of the threat".

French President Francois Hollande was set to hold his first formal meeting with victims of the November 13 attacks in Paris on Monday, three days after Belgian police captured key suspect Saleh Abdeslam.

Georges Salines, the head of one victims' group, 13 Novembre: Fraternite et Verite (November 13: Fraternity and Truth), said Hollande would be quizzed on his strategy for fighting the Islamic State jihadist group, which claimed the assault.

Work to clear the last makeshift shelters from part of the migrant camp known as "The Jungle" in the northern French port of Calais was completed Wednesday.

Authorities have left just a few structures housing communal facilities such as mosques or canteens in the 7.5-hectare (18.5-acre) southern part of the camp.

France will tell Turkey at a summit with the EU this week it wants more effective cooperation with Ankara on the migrant crisis, but will warn against any attempt at "blackmail", Prime Minister Manuel Valls said Tuesday.

Palestinian leaders expressed hope for a new French push for peace efforts in talks with a Paris envoy on Tuesday, after he faced skepticism in meetings with Israel.

Pierre Vimont, France's point man on efforts to hold an international peace conference by the summer, held talks Tuesday in Ramallah with Palestinian President Mahmud Abbas, foreign minister Riad al-Malki and top negotiator Saeb Erekat.

French Foreign Minister Jean-Marc Ayrault hit out Sunday at comments by his Syrian counterpart that removing President Bashar Assad would cross a "red line" in the negotiations, describing them as a "provocation" and a "bad sign" for the attempts to find peace.

Muallem said in Damascus Saturday: "We will not talk with anyone who wants to discuss the presidency... Bashar Assad is a red line."

French police arrested 14 people on Saturday after a far-right group took to the streets for an anti-immigrant rally in the port town of Calais, where thousands of migrants are living in improvised camps.

The roughly 80 activists blocked off two bridges close to the city center and burned tires, waved banners and set off smoke bombs, police and officials said.