'Have you read any of Mlle Larivière's stories? Well, you will. She thinks that in some former Hindooish state she was a boulevardier in Paris; and writes accordingly.' (Ada, 1.8)

The author of La rivière de Diamants, Mlle Larivière (Lucette's governess) adopts the penname Guillaume de Monparnasse (1.31). The author of La Parure (who does not exist on Demonia), Guy de Maupassant describes the hero of his novella Yvette as follows: Jean de Servigny, small, slender, a trifle bald, rather frail, with elegance of mien, curled mustache, bright eyes, and fine lips, was a man who seemed born and bred upon the boulevard.

Maupassant also speaks of boulevardier in The Effeminates: But the most irritating of girl--men is assuredly the Parisian and the boulevardier, in whom the appearance of intelligence is more marked and who combines in himself all the attractions and all the faults of those charming creatures in an exaggerated degree in virtue of his masculine temperament.

On the other hand, I came across бульвардье in Don Aminado's memoirs "Поезд на третьем пути" (The Train on a Third Track, 1954): И как же забыть завсегдатая генеральных репетиций, первых представлений и первых рядов, рисовальщика и карикатуриста, остроумного, весёлого, или притворявшегося весёлым, всей повадкой своей напоминавшего парижского бульвардье, в шляпе набекрень, в выхоленной бородке с моложавой проседью, милейшего, беспокойнейшего Мих. Сем. Линского, предварительно переменившего немало газетных рубрик и немало псевдонимов, которому на каком-то интимном чествовании, - в Одессе обожали юбилеи и чествования, - кажется, Корней Чуковский преподнёс это сохранившееся в памяти посвящение:

Ты прежде принцем был де-Линь,
Потом ты просто стал де-Линь,
Ну что ж, линяй, брат, дальше...

A "boulevardier" living in Odessa, Linski reminds one of Lenski (VN's tutor in Speak, Memory; btw, the author of the above-quoted lines, Korney Chukovsky is also mentioned in VN's memoirs).

Odessa is the setting of Mayakovski's poem "Облако в штанах" (The Trousered Cloud, 1916). In "Верлен и Сезан" (Verlaine and Cézanne, 1925) Mayakovski mentions Boulevard Montparnasse:

Направо от нас -
Boulevard Montparnasse,
налево -
Boulevard Raspail.

Туман - парикмахер,
                  он делает гениев -
загримировал
            одного
                  бородой -
Добрый вечер, m-r Тургенев.
Добрый вечер, m-me Виардо.

Turgenev spent his last years living with the Viardot family in Bougival (the setting of Maupassant's Yvette). On September 20, 1875, the writer moved to the new-built chalet at his and Viardot's villa Les Frênes ("The Ash-Trees") in Bougival. All the hundred floramors [Eric Veen's Villa Venus] opened simultaneously on September 20, 1875... (Ada, 2.3)

Maupassant is the author of La Maison Tellier and Boul de suif (both the brothel and the whore are mentioned in The Gift). In Ada (1.2) Demon Veen watches the hilarious stage version of a famous Russian romance: At an invisible sign of Dionysian origin, they all [young gardeners wearing the garb of Georgian tribesmen and servant girls in sharovars] plunged into the violent dance called kurva or 'ribbon boule'... Kurva Moskva ("Moscow the whore" in a poem by Mandelshtam) was mistranslated by Lowell as "Moscow's ribbon of boulevards." On the other hand, Baron d'O. (the main character in the performance watched by Demon) reminds one of Mademoiselle O, VN's French srory about his governess that, when translated, became a chapter in Speak, Memory.