The Romans called the place Lutetia , or Lutetia Parisiorum . The city was called Lutetia ( more fully , Lutetia Parisiorum , `` Lutetia of the Parisii '' ) , during the Roman era of the 1st to the 6th century , but during the reign of Julian the Apostate , ( 360 â `` 363 ) the city was renamed Paris .