Published at the time of the centenary celebrations of the 1905 law on the separation of Church and State, this work underlined the antiquity of the Muslim presence in France and recalled the colonial refusals to apply this law to Islam. This reissue coincides with the celebration of the centenary of the Paris mosque where old clichés are recalled. The new management of this building, which has especially marked the architectural annals, seems to ignore its history and is content to borrow from Lyautey the slogan of "the mosque-tribute to the Muslim fighters of the Great War", and from Herriot the public financing of an “Institute” and not of the mosque. Real history tells us that when the “Committee for a Mosque in Paris” was created in 1895, Sultan-Caliph Abdelhamid sent President Félix Faure a check for 500,000 francs. The law reported by Herriot in 1920 granted the “Société des habous”, responsible for the project, funding of... 500,000 francs. Is it a coincidence? Gouraud's appointment as head of the “Mosque Committee” took place after the deterioration of France's image in a land of Islam caused by the bombardment of Damascus by this general's heavy artillery. Did the media coverage of the inauguration of the mosque have to do with the thousands of Syrian deaths more than with the Muslim soldiers of the First World War? Lyautey, who tolerated the "mosque, easy to monitor", found the Institute financed by Herriot "dangerous" and sabotaged it on the grounds that it "risked" opening the "minds" (sic) of young people Muslims. The intellectuals of the “Muslim Brotherhood” of 1907 who supported the project of this institute wanted to make it a mecca for the “break with the Algerian morals of France”. They were sidelined in favor of a more or less religious bureaucracy which seems to serve as a model for the current “representatives” of Islam in France. Don’t these anti-colonialists deserve to be celebrated as a priority? And shouldn't their theory on "the spirit of modernity in Islam" be taught in institutes worthy of the name? By offering answers to these questions and a few others, this reissue helps to measure the path that remains to be taken so that relations with Islam are finally based on republican secularism. In this period of celebration of dates in colonial history, these reminders are also an encouragement to remedy the absence of Islam in France from the historiographical landscape and to study new forms of the use of religion for others. purposes.