How To Write Address On Envelope France . Secondary address information (apartment number, etc.) optional. Otherwise, separate the information across two lines. How to Address an Envelope All the Different Ways JAM Blog from www.jampaper.com Write the street address or post office box number on the third line. Sending mail to france includes writing a french address. by la poste (the french postal service) Finally, write your city, state, and five digit zip code under your street address.