It is not the first trial of its kind but it may turn out to be the most important and lead to the virtual elimination of the practice in France. For the first time, the prosecution has been brought because one of the victims had the courage to complain to the authorities when she was an adult.
Campaigners against female circumcision have long hoped that the mutilations would disappear as African immigrant communities became more integrated in French society. French doctors say it is becoming increasingly common for teenage girls of African origin to go to family planning clinics and complain that their boyfriends - often from different ethnic backgrounds - find them "abnormal".
"No one had ever told them that they had been mutilated," said Dr Emmanuelle Petit, who works in a mother-and-child clinic in a Parisian suburb.
Depending on the country of origin, circumcision involves the removal of the clitoris, without anaesthetic, and sometimes the amputation of other parts of the genitalia. Usually the mutilation is performed when the girl is a few weeks old but it is sometimes carried out up to the age of 10.
Fewer and fewer young women of African origin living in France are putting theirdaughters through the ordeal, Dr Petit said. Where almost 100 per cent of girl babies in African immigrant families were circumcised 15 years ago, "there are hardly any cases today".
Almost all of the cases in the trial in Paris involved mutilations that occurred 10 years ago or more.
Police telephone taps proved, however, that the principal accused, Hawa Greou, 52, a professional circumciser, was practising up to her arrest in 1994 and that, contrary to her claims, knew that such mutilations were illegal in France.
She has been in detention awaiting trial for four years, following a complaint by a then 18- year-old Malian woman, Mariatou Koita. Ms Koita, now a 22-year-old law student, appeared in court this week. Since she identified Ms Greou as the woman who circumcised her when she was eight years old, Ms Koita has been ostracised by her family.
The 27 accused - all mothers of victims, apart from "Mama" Greou - face up to 15 years each in prison.