The gathering of world leaders in Paris to negotiate ways to combat climate change should provide "a political impulse" to reach a "binding" and "ambitious" deal, French President Francois Hollande said on Sunday.

"If I had to judge the presence and number of contributions, I would say that the target is met. But we have an agreement to seek and conclude," Hollande said during a joint press meeting with Canadian Prime Minister Justin Trudeau.

About 150 heads of states and governments will participate in the 21st United Nations climate conference, widely considered as the last chance to forge a crucial accord to trim global warming by 2 degrees Celsius by the end of the century.

At Copenhagen summit in 2009, negotiations failed to limit greenhouses and the developed nations' promise to grant 100 billion U. S. dollars to world's poorest countries to cope with climate change remained on paper.

Noting "signals of hope", the French President stressed the need to "convince all the countries because a consensus must be found during the conference so that there will be an ambitious and binding agreement."

Earlier on Sunday, Hollande met UN Secretary General Ban Ki-moon "to discuss how to work together to ensure the success of the Paris Conference on climate" and "the conditions that must be met to have an ambitious result", French presidential office the Elysee said in a statement.