A total of 39 men and 26 women were on trial in Angers
Sentences ranged from four months suspended to 28 years for second-time offenders. Three people were acquitted.
Those who received the longest jail terms were key figures in the vast paedophile ring that operated in a deprived area in the town of Angers.
Sixty-five people were tried on charges of sexually abusing 45 children aged between 6 months and 12 years old.
Defence lawyer Jean-Noel Bouillaud told French radio he was happy with the sentences.
"Overall I would describe this ruling as balanced... You will remember that we feared a mass trial... When you look at the ruling as a whole, the impression is that, on the contrary, the court paid great attention to every individual case."
Central figures
The defendants included 39 men and 27 women, aged 27 to 73.
There were originally 66 accused, but charges against one defendant were dropped because of ill health.
A man known simply as Philippe received a sentence of 28 years for his role in the abuse.
His son, Franck, was sentenced to 18 years in prison and Franck's former partner, 32-year-old Patricia, received a 16-year jail term for her crimes.
ANGERS TRIAL Began on 3 March 65 people accused of abusing 45 children 25,000 pages of evidence stored on CD-Rom Prosecution case: 430 pages Some 250 witnesses 60 lawyers - 51 for the defence, 9 for the prosecution Trial cost: 5m euros (£3.5m)
Sex ring shocks France French justice in the dock Victims' 'living hell'
Much of the abuse is believed to have been carried out at the couple's flat in the western town.
Franck was convicted of raping three of his own children.
Two brothers involved in the ring received combined sentences of 54 years.
Eric, described as an "ogre" and known to the children as "the fatty" , was sentenced to 28 years and his brother, Jean-Marc received 26.
One social worker received a jail sentence of one year with six months suspended for failing to report the sexual abuse on some of the youngsters.
Most of the families involved in the case had been visited by social workers, but for years no action was taken, says the BBC's Jacky Rowland in Angers.
Matthieu Garnier of Angers social services says there must be better communication in future between social workers and the police.
"It's obvious that we must make an effort to work together. The paradox is that in this town, we were not too bad at exchanging information," he told the BBC.
Lawyers involved in the case have described it as a distressing example of the breakdown of moral and social values on a council estate.
The court has yet to rule on compensation and care for the many child victims.
Confused
The crimes took place between January 1999 and February 2002 in Angers' Saint-Leonard district.
Full identification of the suspects was banned to protect the identity of the children.
During the five-month trial, jurors heard pre-recorded evidence given by some of the children.
Correspondents say the accused - many of whom were unemployed and lived on benefits - said little in court and seemed confused by the proceedings.
About 20 of them acknowledged some of the charges, while others said they knew nothing about the paedophile ring.
Defence lawyers had called for many acquittals, citing lack of evidence.
They also pointed out that many of the accused had suffered abuse as children themselves.
The biggest child abuse case in the history of France, involving 45 abused children and 65 defendants, ended today with the conviction of all but three of the accused.

The court in Angers handed down sentences ranging from four months suspended to 28 years for, among others, Philppe V., the key accused. The court found that he, along with his son Franck V. and Franck's former spouse, Patricia M., was one the instigators of a sex ring that abused 45 children, mostly in the couple's flat.

The abuses of children aged between six months and 12 years took place in a poor and deprived area of the western french town of Angers. Many of the defendants were poor and lived on benefits and some were mentally impaired. About 20 of them admitted to the charges, while others claimed to have never heard of a sex ring.