Three photographers have defended themselves against charges of invasion of privacy for taking pictures at the scene of the crash that killed Princess Diana.
The court case follows a complaint filed by Mohamed Al Fayed and comes after the photographers were cleared of manslaughter charges in 2002 in relation to the high-speed crash.
Jacques Langevin of the Sygma/Corbis agency, Christian Martinez of the Angelis agency and freelancer Eric Chassery face one year in prison and fines if convicted.
A judge dismissed the case against five other photographers present at the crash scene in 1997.
Of the three, only Langevin and Chassery were in the courtroom as the trial began in Paris. It was not clear why Martinez was not present.
The three men were among the celebrity photographers who pursued the Mercedes carrying Diana and Dodi Fayed, on August 31, 1997. Driver Henri Paul also died in the crash in a Paris tunnel.
The photographers were being tried only for pictures they took of Dodi Fayed. Diana's relatives and the British royal family are not plaintiffs in the case.
Photos taken at the site were confiscated and never published. A verdict is expected to be set for a later date.
France's highest court has already dropped manslaughter charges against the photographers in the case. An investigation into the crash concluded Henri Paul had been drinking and was driving at high speed.