The two bars that she ran catered to gay and lesbian clients and were frequently discussed in court and police documents, as well as in literary publications and memoirs.

She earned only 18 sous[1] (a sou was 1/20th of a franc, or approximately the equivalent of 8 1/2 British pence[5]) for a day's labor, and in later life remembered her poverty during this time.

[4][8][Note 1] Art critic Émile Schaub-Koch [wikidata] and poet Sylvain Bonmariage [fr] both wrote literary works describing a three-month drinking binge in 1888 which involved Dumont, the courtesan Lucy Jourdan, the artist Henri de Toulouse-Lautrec, and another friend, Armande Brazier (also known as Armande la Borgne), who would later operate the lesbian bar Le Hanneton (The June Bug) on Rue Pigalle [fr].

Patrons of bars and entertainment venues could not be arrested for homosexual behavior, but they could and were targeted for public obscenity, corruption, solicitation, or failing to register as a prostitute with the state.

[11] Some brasseries (a type of restaurant that served simple food and alcoholic beverages, especially beer) also were involved in prostitution; in the Montmartre neighborhood, some were targeted at lesbian clients.

[17] Unlike other lesbian establishments of the era like Le Hanneton, Dumont did not rely on advertising and La Souris was unmarked by any signage.

[3] She hosted meetings at La Souris for the French Bulldog-Owners Club, which included writers like Natalie Clifford Barney, Colette, and Renée Vivien, among others.

[13] Gerstle Mack, who wrote the first English-language biography of Toulouse-Lautrec,[20] called La Souris "the most famous lesbian restaurant of the period".

[12] His drawings and sketches of Dumont, her bulldog Bouboule, and other clientele of the establishment, as well as his introduction of friends to the brasserie, propelled it into a gathering place for avant-garde artists and intellectuals.

[12] It was also frequented by prostitutes, kept women, performers, and patrons who wished to smoke, partake of morphine or ether, gamble, or watch the entertainment provided.

[25] The dinner featured rainbow trout in lobster sauce, Portuguese beef fillet, chaudfroid of poultry, jellied York ham, hare terrine, and Neapolitan salad followed by bombe glacée and dessert.

[24][26] Bulldogs like Bouboule had first become fashionable among lesbians and gender non-conforming women in Paris, before the breed's popularity had grown among the upper classes.

[31] Among his works that feature Bouboule are Le Marchand de Marrons (1897, The Roast Chestnut Merchant), À La Souris: Madame Palmyre et son chien (1897, Madame Palmyre and Her Dog),[32] and likely L'cheval et le chien à la pipe (1898, The Horse and the Dog with a Pipe), in the collection of Otto Gerstenberg.

[39] She signed a ten-year lease for the space located at 5 Place Blanche with partners Albert and Marcel Verdier, brothers whose parents were restaurateurs.

[40] Catering to both gay men and lesbians, Dumont purposely reached out to queer women like Colette and her partner Missy, as well as actors and singers like Louise Balthy [fr], Édouard de Max, and Véra Sergine,[41] and writers like Jacques d'Adelswärd-Fersen.

[44] Colette, who frequented the bar with Missy, described Dumont as motherly, showering them with presents, cooking their favorite foods, and showing off her bulldog puppies with exceeding pride.

[13][41][45] She wrote in "Sémiramis Bar", published in March 1909 in La Vie Parisienne, a thinly-veiled description of Dumont saying that the proprietor resembled a bulldog, wore her red hair fashioned into a bump just above the forehead with a chignon in the back, and had a chest like a Spanish balcony.

[46] Paul Leclercq [fr] noted that while Dumont looked like her dog and always seemed ready to bite, in actuality, she was "exceedingly kindhearted",[21] and others said she had a "heart of gold".

[54] When World War I began and Montmartre was forced to close its entertainment houses for security reasons, Dumont took advantage of her status as a restaurateur to expand the business into the pharmacy next door.

By commercializing and commodifying the queer community, and encouraging tourism to partake in the bohemian pleasures offered in Montmartre, she helped propel that area of Paris to hold a central position as a capital of gay entertainment.

[11] Numerous artists and illustrators flocked to Montmartre during the Belle Époque period to sketch the clientele, couples, owners of bars, and entertainment venues that catered to the growing night life industries.

Albert stated that La Souris and Palmyr's Bar were important venues of queer life during the period, bringing lesbians in particular from invisibility into public space.