N ` Djamena was founded as Fort-Lamy by the French commander Ã mile Gentil on May 29 1900 . It was named after AmÃ dÃ e-Fran Ã ois Lamy . N ` Djamena was founded as Fort-Lamy by French commander Ã mile Gentil on May 29 , 1900 , and named after AmÃ dÃ e-Fran Ã ois Lamy , an army officer who had been killed in the Battle of KoussÃ ri a few days earlier .