As uncertainty mounted over the hard-fought pact's future under US President Donald Trump, China's leader Xi Jinping vowed to protect it.
China and France "should protect the achievements of global governance, including the Paris Agreement," the foreign ministry in Beijing quoted Xi as telling his newly-elected counterpart, Emmanuel Macron, in a phone call.
Trump has yet to announce whether he intends keeping a campaign promise to withdraw Washington from the hard-fought agreement in whose birth his predecessor, Barack Obama, and Xi were instrumental.
The May 8-18 Bonn meeting is meant to start designing a "rulebook" for implementing the global deal to limit average global warming to two degrees Celsius over pre-industrial levels.
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This is the ceiling at which scientists say we can avoid worst-case-scenario climate change impacts - rising seas, harsher droughts, more intense storms, disease-spread and conflict over dwindling natural resources.
A total of 196 countries are now parties to the climate deal clinched in 2015 after years of tough bartering.
With the rest of the world waiting for finality ever since, the new president has said he will make his decision before the next G7 meeting on May 26-27 in Sicily.
Yesterday, the US deputy assistant secretary for international environmental affairs, David Balton, said the decision would likely be taken "over the next couple of weeks, but not this week."
The Bonn talks have been overshadowed by fears that the world's number two carbon polluter will pull out of the agreement and throw the process into disarray.
Massoud Rezvanian, speaking on behalf of the Like-Minded Developing Countries, a negotiating bloc representing more than half the world's population in China, India, Africa and the Arab world, said the agreement "must be observed and not be renegotiated."
The US did send a delegation to the talks, led by Obama- era negotiator Trigg Talley, who declined to comment on the team's brief.
A State Department official told AFP: "We are focused on ensuring that decisions are not taken at these meetings that would prejudice our future policy, undermine the competitiveness of US businesses, or hamper our broader objective of advancing US economic growth and prosperity."
This is key, as current pledges place the world on track for warming much higher than the ceiling of two degrees Celsius written into the agreement.
The Bonn meeting is tasked with starting work on rules to guide countries in implementing the Paris pact - how to measure and report on their greenhouse gas emission cuts, for example. The work must be finished by next year.