French President Francois Hollande met Pope Francis on Wednesday to thank him for his solidarity with the French people after attacks by Islamist militants, including the killing of an elderly priest in July.

A professed atheist, Hollande started his brief, private trip to Rome and the Vatican with a stop in San Luigi dei Francesi, the 16th century church of the French community in the Italian capital.

He stood in silence for about 10 minutes in front of a small side chapel that became a place of prayer and remembrance after the wave of Islamist attacks in Paris in November that killed 130 people.

To the left of the altar, near bowls where visitors leave notes to honor victims of terrorism, was a photograph of Father Jacques Hamel, the French priest killed on July 25 in the town of Saint-Etienne-du-Rouvray.

Hamel was saying mass when attackers stormed in, forced the 85-year-old to his knees and slit his throat while chanting in Arabic.

Speaking to reporters outside the church before heading to the Vatican, Hollande said he wanted to thank the pope for his solidarity with France over the attacks.

He said that in a telephone conversation after Hamel's murder the pope "let me know that he felt like a brother standing alongside the French people".

Hollande, who has not ruled out running for re-election next year, said that apart from the attacks in France, he wanted to discuss with the pope the flight of Christians from the Middle East because of war, and the refugee crisis in Europe.

Hollande made an official visit to the Vatican in 2014.