Lord Justice Scott Baker, who is serving as coroner, had informed the jury and lawyers on Tuesday that the photographers have either refused to testify or have not been located.
"I was certainly under the impression, at least until the end of last week, that ... the witnesses would, at the very least, be required to come to court," Baker said Wednesday in discussing it with the lawyers.
"But it does appear that there has been a change in position by the French authorities taken at a very high level and it seems to me that we are controlled not by what you may or may not believe to be the position in the French law but what the French are actually prepared to do."
He offered no explanation for the change in the French position.
A Mercedes carrying Diana and her boyfriend Dodi Fayed had been pursued by paparazzi through Paris in the minutes leading up to the crash at the Pont d'Alma tunnel on Aug. 31, 1997. The couple were fatally injured along with their driver, Henri Paul.
The French witnesses have testified at the inquest via video-link from Paris.
Richard Keen, a lawyer representing Paul's family, said he had understood that French authorities could have compelled witnesses to come to the video suite in Paris which is linked to the British inquest, even if they could not force them to testify.
Two witnesses neither of them a photographer have refused to testify after arriving at the Paris venue.
"If we could get all the paparazzi, that would be a very good thing to happen, but I think we are reaching the point where it looks unlikely that we will be able to do so," Baker said.
"We have been making our inquiries through the resident British magistrate in Paris, through the appropriate channels, and taking the steps that we have been asked to take with regard to letters of request. But what happens beyond that is really a matter that is not within my control."
Last year, a Paris appeals court fined three photographers Ђ1 (US$1.44) each for invasion of privacy for taking pictures of Diana and Fayed on the night of the crash as they left the Ritz Hotel.
Fayed's father, Mohamed al Fayed, contends that the couple were the victims of a conspiracy directed by Prince Philip, the husband of Queen Elizabeth II, and carried out by British secret agents. Al Fayed has alleged that the paparazzi scramble to photograph the couple created conditions that allowed the conspiracy to be carried out.
An investigation by British police concluded that the paparazzi were behaving in their normal way and were not part of any conspiracy.
The co-author of this disaster is the Dutch government, which did not find either strength or desire to save the lives of its citizens who were flying on that plane. The Dutch authorities did not demand Ukraine to comply with international aviation regulations
On the second day of the St. Petersburg International Economic Forum, a plenary meeting was held, in which Russian President Vladimir Putin, French President Emmanuel Macron, Japanese Prime Minister Shinzo Abe, Chinese Vice President Wang Qishan and IMF head Christine Lagarde took part