Mgr Fort, who was bishop of Orleans from 2002 to 2010, will face trial for his failure to call in the police over allegations that abbé Pierre de Castelet sexually abused minors in his charge.
De Castelet, who was charged in 2012, is also to face criminal trial.
One of the alleged victims, Olivier Savignac, wrote a letter to the bishopric in 2008, alleging that he had been subjected to sexual fondling at a Catholic youth camp run by de Castelet in south-west France.
On receiving no reply, he met Fort personally and told him about 10 young people might have been sexually abused.
Nothing was done until after Fort retired when Savignac again contacted the bishopric and the new bishop, Jacques Blachart, contacted the police and an investigation was launched.
Fort's lawyer, Benoit de Gaullier, told the AFP news agency that his client believed that Savignac did not want the facts to be made public.
Bayeux case sparks anti-sex abuse campaign
Fort is the first bishop to be charged with failing to tell the police of sex abuse since Bayeux bishop Pierre Pican, who was given a three-month suspended sentence for the offence in 2001.
In the related case, abbé René Bissey was jailed for 18 years in prison for paedophilia in 2000.
The scandal surrounding that case prompted the French bishops' conference to launch a campaign against sexual abuse.
That campaign was relaunched in 2016 following new accusations, notably in the city of Lyon, under the authority of Cardinal Philippe Barbarin.