Leblanc also wrote two notable science fiction novels: Les Trois Yeux [fr] (1919), in which a scientist makes televisual contact with three-eyed Venusians, and Le Formidable Evènement (1920), in which an earthquake creates a new landmass between England and France.

In 1905, Pierre Lafitte, the director of the monthly Je sais tout, commissioned a short story from Leblanc, that was to be in the vein of A.J Raffles by Ernest William Hornung and the adventures of Sherlock Holmes.

Two years later, the book Arsène Lupin, Gentleman Burglar was released, containing the first nine stories depicting the character that were published in the French magazine Je sais tout.

By 1907, Doyle or his representatives had threatened legal action over the unauthorized use of the character, and Leblanc's following collection of stories was titled Arsène Lupin versus Herlock Sholmes.

[9] Maurice Leblanc received the Legion of Honor on January 17, 1908,[10] presented by then Under-Secretary of State for Fine Arts, Étienne Dujardin-Beaumetz [fr].

While a supporter of French radical socialists and free-thinker in his early age, Leblanc became more bourgeois around the time of the First World War.

In 1918, Maurice Leblanc bought a half-timbered Anglo-Norman house in Étretat (which he would name Clos Lupin), where he wrote 19 novels and 39 short stories.

[11] Faced with the imminent war with Nazi Germany,[a] he left Clos Lupin in 1939 and took refuge in Perpignan, where he died of pneumonia in 1941.

Maurice later fell in love with Marguerite Wormser (1865-1950) who already had a son Claude Oulmann (1902-1994), who was subsequently authorized by decree to bear the name of Leblanc.

Maurice had health problems and sank into a depression, which was compounded by Marguerite's divorce from her first husband taking time to go through the courts.

[citation needed] Arsène Lupin's exploits took place in the capital and in Pays de Caux, which Maurice Leblanc knew well.

Inspired by one of the Lupin books, he tries to avenge his father's wrongful accusation of stealing a necklace years earlier.