France’s top climate ambassador has said she is very concerned at the slow rate of progress on a negotiating text that will form the basis of a new international deal on global warming in Paris later this year.

But Laurence Tubiana also said that negotiators from nearly 200 countries were making headway on the document, and made clear that the French government wanted to see serious progress on the text by October.

The comments, in an interview with the Guardian, came as climate ministers met last week to advance international climate talks before a crunch UN summit in Paris this November and December.

The UN secretary general Ban Ki-moon said in June that the negotiations were proceeding at “a snail’s pace” after a fortnight of talks in Bonn cut the 90-page text by just four pages. Last Friday a new streamlined version was published, with the two officials overseeing it warning the “pace was slow” and there was an “urgent need, owing to serious time constraints, to accelerate the work”.

The final document that governments hope to agree in Paris will have to be far shorter - with points of disagreement ironed out and swathes of potential text currently in brackets removed.

“We are all very concerned, but it’s progressing,” Tubiana said, hours before the latest version was published. “What we do as a normal presidency [of the talks] anxious to have a result in Paris not at the last minute, is to say we need something [a better, shorter text] to be cleared in October.”

She said that making the deal legally-binding was less challenging, as only certain elements of any accord would need to be binding.

But she said the most difficult element of an agreement would be the issue of the rich countries most responsible for global warming financially helping poorer countries adapt to climate change, echoing previous comments by the French foreign minister, Laurent Fabius. He said in May that financing would be “decisive” in reaching a deal in Paris.

“I would say the most difficult part of an agreement is finance,” she said. “It has to be clear that money is flowing from developed to developing countries, that’s for sure. It should be a significant share of public money as well.”

What form such finance took after 2020, when $100bn of private and public money is meant to be delivered to poorer countries each year, was “less clear” and “conceptually difficult”, she said.

However, Tubiana was upbeat about the big picture on renewable energy and prospects for a deal in Paris, saying that “powerful interests” in the business world were pushing for a cleaner economy.

Comparing Paris to the run-up to the Copenhagen climate summit in 2009, which ended in scenes of chaos and confusion, she said: “the business sector [then] were looking for a signal to deliver it [the low carbon economy]. Now they are pushing for the signal.”

In June, the heads of Europe’s oil and gas majors wrote a letter to the FT urging governments to take “decisive action” at the Paris summit, and introduce carbon pricing.

Negotiations ahead of Paris were already on a better track than Copenhagen, Tubiana claimed. “Before Copenhagen, there was a disconnect between the political process and technical process at the negotiator level. Here we have a very good connection between the two.”

Tubiana said that while president François Hollande would be inviting heads of state for the first day of the Paris summit to create political momentum, they would not be part of the talks as they were in Copenhagen, when Barack Obama, Angela Merkel and other leaders debated the fine detail of an accord.

“We do not want to recreate the Copenhagen scenario where everybody hopes they will solve the problem. What we do not want is them enmeshed with the process, which would be terribly difficult to manage.”

• This article was amended on 28 July 2015 to make clear that France wanted to see progress on the Paris text by October, not that France would step in by October to take action on the text itself.