Amon Fasileau-Duplantier, known as Monsieur Amon (22 December 1849 – 24 February 1915), was a French coffee and urban real estate entrepreneur established in Costa Rica. Monsieur Amon commercial activities had a deep impact on the Costa Rican society of the latest 19th century due to the foundation of San José's Belle Époque neighborhood which carries his name today as the Barrio Amón. The image of Monsieur Amon is associated to Costa Rican coffee golden age.

Monsieur Amon was born in Bordeaux. He arrived to Costa Rica in his mid-twenties to work at The Tournon Company, owned by his brother-in-law, Mr. Hippolyte Tournon. The company already produced and exported coffee; Monsieur Amon was entrusted to manage the firm and became a respected local figure with a key influence in the social and economic spheres. He started the diversification into urban real estate and electricity production, coinciding with Minor Keith's development of similar activities, leveraging the Atlantic railroad construction and growing banana trade. Amon returned to France in 1899 after being replaced by his nephew, Elois Tournon, son of Mr. Hippolyte Tournon, as the head of the Tournon Company.

Lemistre, Annie. “Amon El Incognito". First Edition. San José, Costa Rica. May 2015.