Renault Chief Executive Carlos Ghosn said negotiators were trying to resolve differences in auto alliance talks between the French automaker, Japan's Nissan and General Motors.

We try to be discreet about our alliance talks. The teams are at work, Ghosn told reporters during the Paris car show on Thursday.

There are significant synergies, and we try to bridge as far as possible the positions of the teams, and these positions are not far away from each other, he said.

Teams of executives from the three automakers began a review of the potential benefits of an alliance in July, prompted by Kirk Kerkorian, a major shareholder in the U.S. automaker.

We decided to give the teams three more weeks to draw up the possibilities and the synergies. Afterwards we will decide whether we go further and how we will do that, Ghosn said, adding that the question of a capital stake would come after this decision.

We don't think we need to see each other before mid-October, Ghosn said after a meeting with GM head Rick Wagoner in Paris on Tuesday, adding the two could speak by telephone if necessary.

There is a lot of speculation about the discussions with GM, and it is not up to us to add to the speculation.

He said the talks were not about 'sentiment'.

We try to analyze in a logical and lucid and rational fashion the possible synergies. Then the question is, 'Is it worth it, and what is the best way to make it happen'? Ghosn said. So far we did not make this conclusion, but we are piling up all the arguments to make a decision.

The first question is about the synergies. After we answer that, we can eventually make the second step about how to make it happen, and then the discussion about a potential capital alliance can happen, he said.