The name was changed to N ` Djamena ( taken from the Arab name NiÇ Ä mÄ `` nÄ , meaning `` place of rest '' ) by the President FranÃ ois Tombalbaye on April 6 , 1973 . Its name was changed to N ` Djamena ( taken from the Arab name of a nearby village , NiÇ Ä mÄ `` nÄ , meaning `` place of rest '' ) by the President FranÃ ois Tombalbaye on April 6 , 1973 , as part of his authenticitÃ program of Africanization .