At the end of his life, he led a fight for pacifism and campaigned to make the city of Brussels a “federal district of the world”.
[1] In September 1888, then in the middle of the Popelin affair, he published a major pamphlet 'La femme-avocat', in which he defended the entry of women into the legal profession.
[4] In 1892 he published a work of more than 600 pages, Essay on the political status of women, in which he defended feminism and was echoed in the press and was an international success.
Frank denounces injustices and speaks out in favor of gender equality:[4] Society will continue its rational march to finally arrive, through successive transformations, at civil and political gender equality, which will be, in the future, one of the cardinal principles of constitutional law (p. 223) On this subject the New York Herald describes his work in the following terms:[4] This is probably the most voluminous and comprehensive work ever devoted to the social and political condition of the fairer sexThese moderate feminist positions are sometimes well received in the press, especially when it evokes the creation of a feminist organization.
[4] He also seeks to increase support for his cause by sending copies to such personalities as the countess of Flanders or the baron of Rothschild, as well as foreign feminists such as Wilhelmina Drucker, who congratulated him warmly.
[11] He leads the organization as Secretary General and continues to write books on feminism such as La femme dans les emplois publics.
In his writings he touches on all aspects of women's lives, from the education of young girls, to the care of mothers, to maternal insurance.
[1] He quickly renewed his ties with the league, attended dinners and participated in the creation of the first International Feminist Congress, which was organized in Brussels in 1897.
[1] Frank also continues to maintain correspondence with many feminists,[1] including in particular the Dutch Wilhelmina Drucker, with whom he frequently shares accounts of the situation in Belgium.
[13] During this period, he also focused his activism on access to higher education for women and founded the 'Œuvre des conférences féministes' at the ULB.
In particular, he advocates feminism as a remedy for this scourge:[1] Only the active, intelligent and conscious cooperation of women will be able to eradicate the alcoholic evil from all peoples.
[2] Frank seeks to attract the support of philanthropists to his project, including Ernest Solvay and Andrew Carnegie.
On June 25, 1905, he receives the support of the King of the Belgians Leopold II, in his idea to make Belgium "a center of the world institutions that will be created in the future ".
[15] Frank also proposes to create a celebration of the centenary of the Battle of Waterloo in the hope that this would mark the beginning of a period of world peace.
[2] As the First World War broke out, Louis Frank collected postcards illustrating the greatness of Belgium in albums entitled "Souvenirs".
[2] According to Françoise de Bueger-Van Lierde, both his avant-garde ideas, his exaggerated pretensions and his Jewish origin in a hostile climate played to his disadvantage.