The French government says no ransom was paid for two hostages returning to France after a four-month captivity in Iraq.
Governments have been reluctant to pay ransoms for hostages
Prime Minister Jean-Pierre Raffarin told a group of politicians there had been "neither a demand nor a payment" for the freedom of Georges Malbrunot and Christian Chesnot.
The men's captors said they were freed because of France's anti-war stance.
But the country's press has been full of the "mystery" surrounding their release - and says questions will be asked.
"There has been feverish speculation," Charles Heyman, a senior analyst at Jane's Consultancy Group, told the BBC.
"But no-one really knows."
Reluctance to 'reward'
Governments have been reluctant to pay ransoms for hostages taken in Iraq and elsewhere in order not to encourage further abductions.
"Terrorism should not be rewarded," French politician Herve Mariton told the BBC.
The French journalists' captors - the Islamic Army in Iraq (IAI) - initially demanded that France scrap a law banning Muslim headscarves from being worn in schools - a demand shunned by France.
They were later reported to have requested a ransom, but a statement quoted by Arabic TV channel al-Jazeera on Tuesday said the reporters were released for political reasons.
The sister of Mr Chesnot said she would not be concerned if a ransom had been paid.
"The most important thing is that Christian and Georges come back home," Anne-Marie Chesnot told the BBC.
When two Italian hostages were freed in Iraq in September, the government in Rome denied paying a ransom.
However, a senior Italian politician said at the time that he believed a ransom of $1m or more had been paid for the two aid workers, Simona Pari and Simona Torretta.
Three Indian truck drivers held hostage in Iraq were freed a few months ago after their Kuwaiti employer paid $500,000 to the militants, whom it described as "purely extortionists".
Hundreds of Iraqis, including businessmen and doctors or their relatives, have been kidnapped for ransom. This is a common phenomenon and goes largely unreported.