This dissertation considers Gervais-François Couperin (1759-1826) and his offertories, providing a performance guide relevant to French organ literature of the beginning of the nineteenth century. To fulfill this purpose, the research is divided into five chapters and a conclusion. Chapter 1 is an introduction explaining the purpose of the research and significance of the research. Chapter 2 presents the Couperin Dynasty and their lineage at Saint-Gervais, as well as the evolution of the musical market in the middle of the eighteenth century in Paris, which influenced Gervais-François Couperin's Offertories. Chapter 3 to Chapter 6 present the performance guide to playing Gervais-François Couperin's offertories: Chapter 3 focuses on the significant development of the French organ building in the 1800s and the registration of Grand-Jeu. Chapter 4 deals with the addition of the pedal, and Chapter 5 focuses on embellishment using tremendo (tremolo) and arpegio (arpeggio). Lastly, Chapter 6 offers a guide for adding manual indications where the score did not include them or in places where ambiguities remained. Synthesizing these elements, a newly edited full score of Gervais-François Couperin's Offertory in G Minor is provided in Chapter 7 to exemplify this dissertation's conclusion.