The woman, an Erasmus student, was taken to Cardarelli hospital but her injuries are not life-threatening, Il Mattino reported.
A 24-year-old Italian student was also injured in the explosion in the building on Via Giambattista Basile, a busy street in central Naples.
Fifteen others were safely evacuated.
The blast, believed to have been caused by a gas leak, happened in a workshop on the building's ground floor at around 10pm.
The explosion was so strong it smashed windows of nearby shops as well as car windscreens. One car was also flipped on its side.