The BBC's James Coomarasamy: "The church claims to have 40,000 members in France"

The trial, in the southern city of Marseille, has led to renewed calls for the banning of Scientology in France, which officially regards it as a dangerous cult rather than a religion.

The charges against the seven defendants - who are alleged to have obtained large sums of money from fellow sect-members by fraudulent means - date back to the late 1980s.

Marie-Ange Molina, one of the seven defendants

The case opened amid controversy over the disappearance of 50 boxes of evidence from the Marseille prosecutor's office.

Justice Minister Elisabeth Guigou - who has said France might consider banning the sect - said the loss of the files was simply a mistake. The church says they have been deliberately destroyed.

But it is the third time in a year that evidence against Scientologists in France has disappeared.

The court rejected a defence bid to have the case postponed because the loss of the files would "make a fair trial impossible".

'A Roman circus'

The church itself - which claims some 40,000 adherents in France - has accused the French government of "trying to turn the justice system into a Roman circus.

Not all the files have disappeared in this case

"For 10 years, these defendants have been subjected to outrageous harrassment - jail, hysterical media for the last month, and then the very files that would prove their innocence were destroyed," said Heber Jentzsch, President of the Church of Scientology International.

The group - which figures on a government list of 173 to be tracked and deterred from practising cult activities - says its members are subjected to slander and persecution.

Popular with Hollywood stars

Scientology - founded in 1954 by science fiction writer L Ron Hubbard - teaches that technology can expand the mind and help solve human problems.

The sect has many high-profile Hollywood adherents, including John Travolta, Tom Cruise and Nicole Kidman.

In the United States, the Church of Scientology is regarded as a religion.