French Foreign Minister Michel Barnier has arrived in Egypt at the start of a mission to secure the release of two journalists being held in Iraq.
The journalists disappeared nine days ago
The move was announced by President Jacques Chirac after senior French politicians held emergency meetings to discuss their response to the crisis.
Arabic TV station al-Jazeera broadcast film of the two Frenchmen on Saturday.
It said the group holding them was demanding that France drop its ban on Muslim headscarves in state schools.
The BBC's Angus Roxburgh in Paris says the French government is unlikely to accede to the demand.
He adds that there is consternation in France that its citizens have been targeted by Iraqi militants, as the country has been a vocal opponent of the US-led war in Iraq.
Palestinian leader Yasser Arafat has added his voice to those of the many Islamic leaders calling for the journalists' release.
Describing Mr Chirac as "a good friend of the Palestinian people", he said the "journalists were helping the Iraqi and the Palestinian cause".
Mr Chirac said Mr Barnier would "develop the necessary contacts there and co-ordinate the efforts of our representatives on the scene".
The French president called for the release of Radio France Internationale correspondent Christian Chesnot and Georges Malbrunot of Le Figaro newspaper.
"Everything's been done and everything
will be done in the hours and days to come to make sure that
happens," he added.
The two journalists disappeared nine days ago.
They were reported to have been heading from Baghdad to Najaf.
Al-Jazeera reported that it had received footage saying a group calling itself "The Islamic Army in Iraq" - the same group which reportedly killed kidnapped Italian journalist Enzo Baldoni last week - is holding them.
The pair have extensive knowledge of the Middle East
The TV station said the group described the French law banning religious apparel in public schools as "an attack on the Islamic religion and personal freedoms".
It said the kidnappers wanted France to reverse the ban within 48 hours.
After a meeting on Sunday with French Muslim leaders, Interior Minister Dominique de Villepin said: "French people of all origins and all religions are united in support of our compatriots Christian Chesnot and Georges
Malbrunot. Together, we ask for their release."
The head of the French Council for the Muslim Faith, which serves as a link between the French government and the country's five million Muslims, has condemned the kidnappings as an odious act of blackmail.
Dalil Boubakeur told reporters: "The Muslim community must set itself apart from these schemes, which are reprehensible in the eyes of Islam."
The headscarf ban has led to global protests
Lhaj Thami Breze, head of the Union of French Islamic
Organisations, which has urged schoolgirls to defy the
ban, said the headscarf issue was strictly a French affair.
"We cannot accept any outside interference," he said.
The headscarf ban, which is due to come into effect when students return to school next week, became law in March after months of acrimonious debate.
It is regarded as central to the government's policy of keeping state institutions secular, but has sparked protests at home and abroad, with many Muslims saying they feel unfairly targeted.
The law forbids religious apparel and "conspicuous" signs that show a student's religious affiliation. Jewish skullcaps and large Christian crosses are also forbidden.
Meanwhile, Turkish government officials say two Turkish citizens kidnapped from a construction site in Iraq - named as Ali Daskin and Abdullah Ozdemir - have been released.
A foreign ministry spokesman in Ankara said the two men were now in the Turkish embassy in Baghdad, but gave no further details.
On Wednesday last week, two private Turkish television stations broadcast a video tape threatening that the men would be killed if their company did not stop working in Iraq.