Negotiators at key UN climate talks in Paris that open next week are being told by the French government they must iron out their main differences six days before the end of the talks, according to the foreign minister, Laurent Fabius.

World leaders including Barack Obama, Xi Jinping, Angela Merkel and David Cameron are preparing to fly to the French capital to open the COP 21 negotiations, which begin on Monday and aim to produce an international deal to reduce carbon emissions that will kick in from 2020.

The highly unusual demand by the French hosts is a sign of their confidence that they believe a deal is within sight and that the huge diplomatic push they have made to ensure the talks succeed has not been knocked off course by the terrorist attacks two weeks ago.

But Fabius’s request to have the final version of the negotiating text signed off by next Saturday will be met with scepticism among some observers of the talks. Frequently, previous incarnations of the UN talks have finished one or even two days after deadline.

Fabius vowed in an interview to forge an agreement that would be “universal, legally binding, durable and dynamic”.

In the wake of the attacks, Fabius confirmed that security would be tightened around the conference centre, which is on the outskirts of Paris, near the airport where a planned attack was foiled and not far from the St-Denis district where the attacks were planned. There will be a total lockdown on the area of Paris surrounding the conference centre on Sunday afternoon, when many of the heads of state and government are expected to arrive, in time for the first official day of talks on Monday.

Fabius praised the climate activists who had agreed to call off their planned march through Paris as a result of the attacks. “I have to salute the responsibility of the organisations who would have liked to demonstrate but who understand that if they demonstrate in a public place there is a security risk, or even a risk of panic.”

He said: “The first week [of the fortnight-long talks] will be devoted to reducing the number of options in the text,” in which delegates have suggested multiple alternatives in wording on certain issues. “I will ask that by [next] Saturday midday the text will be transmitted to me, the president of the COP, and at that moment everyone will know where we are and the procedure to follow. Obviously, I hope a maximum number of options will have been lifted but I will have to take into account the situation at that moment.”

In a veiled reference to the situation at the last climate summit in Copenhagen, when negotiations were thrown into chaos by rumours of a draft text that had been circulated to some governments, he added: “I don’t have a text in my pocket that I can pull out. I have found with the delegations that there is a real willingness to move forward, a willingness to be transparent.

“If there is no agreement by Saturday, of course I will take the initiative. I will see the different groups with the facilitators,” he said. “Success is at our door, but it is not yet won.”

Fabius, speaking in his resplendent office in France’s foreign ministry, was in ebullient mood. Amply gilded and frescoed, with French windows looking out on to ornamental gardens on the banks of the Seine, the ministry was built with the intention of impressing France’s many allies, and potential enemies.

The French are hoping that the discord that has marked previous talks, preventing a legal agreement at the last climate summit in Copenhagen in 2009, will be averted by meticulous planning. Fabius, despite his punishing schedule since the atrocities in Paris, has been habitually squeezing questions on climate change into every meeting with his foreign counterparts and heads of state, as has the French president, François Hollande.

Before the talks, governments responsible for more than 90% of global emissions – including all major developed economies and most of the biggest developing nations, such as China and India – have laid out plans for cuts or curbs to their emissions. These will form the centrepiece of any deal, and even if a deal is not reached, these commitments will be hard for governments to renege on.

Fabius said the COP 21 talks were “a success in terms of numbers and actions” pledged by countries on emissions reductions. “If we add together all these contributions, we avoid catastrophe, in the form of the consequences of inaction, a world four, five or six degrees [warmer]. But we are still not at 2C or 1.5C, which is the goal of Paris.”

Scientists estimate that if the world warms by more than 2C on average above pre-industrial levels by the end of this century, the effects of climate change will become catastrophic and irreversible. A 2C limit has long been the goal of UN climate conferences, and current pledges from all countries are estimated to lead to warming of 2.7C to 3C, although the proposed deal has a provision for increased emissions cuts in future.

Fabius urged governments to move beyond the entrenched positions of the past. “We must do our utmost to avoid the blocking of an agreement because of irreconcilable principles. A good approach is to take this issue subject by subject.”

On financing, for instance, he said there was general agreement that rich countries would ensure the funds promised to poor nations to help them cut emissions and adapt to global warming would be forthcoming.

In a pointed reference to one of the countries that may hold out on an agreement, Fabius said: “I was talking to the prime minister of India and he said for the moment my resource is coal, so he is approaching this on how he can make coal more clean.”

But he said that generally the world was moving towards decarbonised energy. “We must not, it seems to me, present this climate question as a constraint, but an opportunity. China is a big leader in the world on solar energy. There are lots of opportunities in different countries,” he went on. “For instance, programmes suggested for Africa – we have to help this development, it can give direct employment, and in the case of Africa can be a factor for growth.”