Marcel Romain Lebrun was born in the 14th arrondissement of Paris in March 1861, the eldest son of the architect Émile Edme Lebrun and Clotilde Anastasie Chomet. By his early twenties he was working as an insurance agent (agent d’assurances) and living at Rambouillet, southwest of Paris.
On 23 March 1882, at the little commune of Autouillet (canton of Montfort-l’Amaury), he married Eugénie Marie Désirée Vandenberghe, a young woman from Menin (Menen), on the Franco-Belgian border in West Flanders. A formal marriage certificate survives, along with a marriage contract drawn the day before at Neauphle-le-Château — the couple had enough property to want it settled by a notary. His parents gave their consent in person; her father, a merchant back in Belgium, consented by act from afar, her mother having already died.
The couple made their home at Saint-Maurice, a working-and-middle-class commune on the Marne just southeast of Paris, where their four children were born between 1883 and 1888: Juliette Emma Marie (who died at three), the twins Georges Marcel and Ferdinand Julien (born 1885 — Ferdinand died an infant), and Paul. Georges Marcel, the surviving twin, was the one who would eventually leave France for Haiti, and through whom this Paris insurance agent became the great-great-grandfather of a family in Florida.