Leo, who will meet abuse survivors during the four-day trip starting on Friday, is also expected to draw large crowds for an outdoor Mass in central Paris and will address French, UN and European leaders in separate events on his whirlwind, three-city tour.
Some 600,000 people have registered to join the outdoor mass on Saturday, near Paris's famed Avenue des Champs-Elysees.
"French Catholics are ... saying loudly that they need the church to find their way in these uncertain moments in world history," said retired French Bishop Marc Stenger, citing the registration numbers.
Leo's agenda in Paris includes speeches to President Emmanuel Macron and other French leaders at the Elysee Palace and to staff at the headquarters of the United Nations culture and education body, UNESCO, which is facing budget shortfalls after US President Donald Trump withdrew from the agency in 2025.
The first US pope attracted Trump's ire earlier in 2026 after criticising the Iran war.
Leo will also lead a prayer service in Paris at the restored Notre-Dame cathedral, in the first visit by a pope since a devastating fire nearly destroyed the Gothic masterpiece in 2019.
Beyond Paris, the Pope's tour includes a stop at the famous Catholic shrine at Lourdes, in southwestern France.
It will culminate in Metz, a town near the German border that was home to the late Robert Schuman, one of the founders of the European Union, for a speech on "the roots of Europe for peace and unity".
Macron has invited leaders from all 27 EU member states to attend the Metz speech, said Charles Personnaz, France's Vatican ambassador.
It was unclear how many would come, he said, given that it coincides with the UN General Assembly meeting in New York.
Leo would meet seven survivors of abuse by Catholic clergy on Sunday in Lourdes, several of those involved said in a statement.
A 2021 report found that some 330,000 French children had been abused by Catholic clergy and lay leaders over seven decades.
Echoing similar reports in the United States, Spain and Portugal, it said the church had shown "deep, total and even cruel indifference" to victims.
French bishops have since introduced compensation and safeguarding measures, but survivors have continued to press church leaders to demonstrate accountability.
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