French President Francois Hollande has called on Iran for help in the Syrian conflict during a Bastille Day speech in which he praised a landmark Iranian nuclear agreement.

Hollande said the deal shows the "world is moving forward" and that "Iran must show that it is ready to help us end the (Syrian) conflict."

But Hollande also said that world powers must carefully watch how Iran uses the billions of dollars in relief from international sanctions it gets in exchange for curbing its nuclear program.

"Now Iran has a bigger financial capacity, we need to be extremely vigilant on what Iran will be," Hollande added in the televised speech.

Meanwhile, French Foreign Minister Laurent Fabius told newspaper Le Monde that the Iran deal was "sufficiently robust" to last 10 years.