France warned on Tuesday that a proposed foreign-backed peace conference bringing together the Syrian regime and the opposition would be "very difficult" to organise.
Washington and Moscow have proposed the conference to push Damascus and the rebels to hold talks in the coming weeks in a bid to find a political solution to the country's civil war.
Dubbed "Geneva 2", the talks aim to revive a stalled process started by foreign powers in the Swiss city last June.
"Clearly France is in favour of Geneva 2, but at the same time it's very difficult," French Foreign Minister Laurent Fabius told RTL radio.
"It's not easy, there must be people from the opposition and people close to the regime who do not have blood on their hands," Fabius said.
Fabius said a preliminary meeting of involved countries would take place at the end of next week.
"We are trying to work (on organising the conference) for the end of May. There will be intermediary steps, at the end of next week probably in Jordan, then maybe in Paris."
A diplomatic source said the Jordan meeting would involve countries in the "Friends of Syria" group that generally supports the opposition.
A meeting of top officials from the United States, France and Britain will take place this Thursday, with Russia and China joining the talks on Friday, the source said. The location for these talks has not yet been set.
"We want to create a transitional government that will take over the powers of (Syrian President) Bashar al-Assad and, as a result, he will be sidelined," Fabius said.