Ministers from more than 190 countries are expected to ratify a major new international climate change agreement - the details of which were announced at around 10:30am GMT (11:30am CET).
The final agreement would include a commitment to keeping temperature rises "well below" 2C above pre-industrial levels with a target of keeping them at 1.5C. Ministers are meeting on Saturday afternoon to decide whether or not to approve the agreement.
Announcing the deal, French foreign minister Laurent Fabius said the potential deal aimed to show: "Our collective efforts are worth more than the sum of our individual efforts."
"In this room you are going to be deciding a historic agreement. The world is holding it breath", he added.
Addressing the hall of delegates, Mr Fabius quoted the late South African statesman Nelson Mandela by saying: "It always seems impossible till its done.
"None of us acting alone can be successful. Success is built collectively."
French President Francois Hollande said if the agreement is reached, it will be the first universally agreed climate change treaty ever.
He said it was potentially "a massive leap for mankind".
Delegations are expected to receive a copy of the draft deal at around 1:30pm (12:30pm GMT) and will then have a few hours to go through it before making the final decision to sign it.
Mr Fabius said the deal also "acknowledged the notion of 'climate justice'".
He announced there will be a five year review system which would see countries review and increase their pledged emissions cuts - a key request by a coalition of countries most vulnerable to climate change.
He also said rich countries will contribute $100bn in finance from 2020 but the BBC reports there is a rumour that this pledge has been moved out of the main agreement text and into the underlying decision text - meaning it is easier to get out of it further down the line.
The issue of "loss and damage" - the recognition that some of the most vulnerable countries need support to cope with irreversible impacts such as inundation of their land from rising sea levels - is a sore spot, with developed countries refusing anything that could open them up to liability or compensation.
As the talks headed past the deadline, tensions began to show with Indian environment minister Prakash Javadekar accusing developed countries of not showing flexibility towards poorer countries.
And Marshall Islands foreign minister Tony de Brum, the driving force behind the "high ambition coalition" of countries including the EU calling for a strong deal at the talks, warned there had been a "co-ordinated campaign to gut the text" of ambition by some countries.
Additional reporting by PA
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