Francis spent the final day of his week-long trip to Africa in the Mauritian capital Port Louis, celebrating mass before an estimated 100,000 people and meeting with government leaders.
The trip fell on the feast day of one of Mauritius' most important figures, the 19th century French missionary the Reverend Jacques-Desire Laval, who ministered to freed slaves.
While Catholics represent less than a third of Mauritius' 1.3 million people, Father Laval is seen as a unifying figure for all Mauritians, most of whom are Hindu of Indian descent.
Francis' visit also came just months after Mauritius scored a major victory at the UN, with a non-binding resolution calling on Britain to return the Chagos Islands, home to the US military base at Diego Garcia, to Mauritius.
Mauritian leaders thanked Francis for the Vatican's "moral support" in the dispute.
In his speech to government authorities, Francis praised the ethnic and religious tolerance that has long characterised Mauritian history, which saw a series of European powers, Dutch, French and finally British, import African and Indian labourers to work the sugarcane fields before the country gained independence in 1968.
"Your people's DNA preserves the memory of those movements of migration that brought your ancestors to this island and led them to be open to differences, to integrate them and to promote them for the benefit of all," Francis said in encouraging continued welcome for migrants who seek a better life today.
Francis also praised the economic development that has turned the country into one of Africa's most prosperous.
But he lamented that income inequalities are widening and that economic growth has not benefited the young, in particular.
He urged the government "not to yield to the temptation of an idolatrous economic model that feels the need to sacrifice human lives on the altar of speculation and profit alone, considering only immediate advantage to the detriment of protecting the poor, the environment and its resources", he said.
Transparency International has said that while Mauritius boasts one of Africa's highest per capita incomes, its growth into a financial centre has come with a cost that was exposed in the Panama Papers and subsequent leaks about shady offshore financial instruments.
The government has called the tax haven allegations false and insisted that it abides by all international standards on transparency and sharing of financial information.
The country's prime minister Pravind Kumar Jugnauth acknowledged increasing economic disparity in his speech to the pope, saying the government was committed to showing solidarity with the most marginal.
"Supporting and comforting the weakest is a duty, a moral imperative that transcends frontiers," he said.
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