An independent commission set up by the French Catholic Church to look at allegations of sexual abuse by clerics began its work by launching an appeal for witness statements.

France's Catholic bishops set up the commission last year in response to a number of scandals that shook the church in the country and also worldwide.

It now has the task to shed light on sexual abuse committed by French clerics on minors or vulnerable individuals going right back to the 1950s.

"For the first time in France, an independent institution is going to launch, over the course of a year, an appeal for witness statements about sexual abuse," said commission president Jean-Marc Sauve.

He has promised that the commission, which is made up of 22 legal professionals, doctors, historians, sociologists and theologians, would deliver its conclusions by the end of 2020.

"It is an important action to be able to give victims psychological or legal help," he said.

The commission opens after Pope Francis in May passed a landmark new measure to oblige those who know about sex abuse in the Catholic Church to report it to their superiors, a move that could bring countless new cases to light.

Mr Sauve expects thousands of telephone calls to a special hotline, as well as messages to an email address, with victims then offered face-to-face interviews in a later stage.

The Bishops' Conference of France agreed in November to set up the commission after scandals that shook the Catholic Church at home and abroad.

French cardinal Philippe Barbarin was handed a six-month suspended jail sentence in March for failing to report sex abuse by a priest under his authority.

Also in March, the Vatican's former number three, Australian Cardinal George Pell, was sentenced to six years in prison by a Melbourne court for sexual abuse.