Lesieur was born into a family of farmers based in Septeuil (Yvelines department), a city of which his father was the Mayor.
Lesieur started working at the age of 15 as a shop assistant for Desmarais Frères (DF), an industrial company specialized in purification and distribution of vegetal oils for lighting purposes.
Disagreeing with DF for family reasons (the Desmarais brothers refused to welcome his sons into the Company), Lesieur resigned in 1908 at the age of 60 and decided to start his own business, using his own assets and funds.
The geographical choice of Coudekerque was made because the Desmarais plants were already installed in Le Havre and L'Huilerie Marseillaise was based in the South of France.
Setting up in the neighbourhood of Dunkerque - third largest port in France for the import of groundnuts after Marseille and Bordeaux - became a natural conclusion.