The Basilica of the Sacred Heart of Paris, commonly known as Sacré-Cœur Basilica
This is what Wikipedia has to say about this church.
The inspiration for Sacré Cœur's design originated in the wake of the division in French society that arose in the decades following French Revolution, between devout Catholics and legitimist royalists on one side, and democrats, secularists, socialists and radicals on the other. This schism became particularly pronounced after the Franco-Prussian War and the ensuing uprising of the Paris Commune of 1870-71. Though today the Basilica is asserted[when?] to be dedicated in honor of the 58,000 who lost their lives during the war, the decree of the Assemblée nationale, 24 January 2010, responding to a request by the archbishop of Paris by voting its construction, specifies that it is to "expiate the crimes of the Commune". Montmartre had been the site of the Commune's first insurrection, and many dedicated communards were forever entombed in the subterranean galleries of former gypsum mines where they had retreated, by explosives detonated at the entrances by the Army of Versailles. Hostages had been executed on both sides, and the Communards had executed Georges Darboy, Archbishop of Paris, who became a martyr for the resurgent Catholic Church. His successor Guibert, climbing the Butte Montmartre in October 1872, was reported to have had a vision, as clouds dispersed over the panorama: "It is here, it is here where the martyrs are, it is here that the Sacred Heart must reign so that it can beckon all to come".