According to IMDb:
Inspired by the story of Merhan Nasseri, an Iranian refugee. In 1988, he landed at Charles de Gaulle Airport near Paris after being denied entry into England because his passport and United Nations refugee certificate had been stolen. French authorities would not let him leave the airport. He remained in Terminal One, a stateless person with nowhere else to go. He has since been granted permission to either enter France or return to his own country. He instead chooses to continue to live in the terminal and tell his story to those who will listen. Reportedly, his mental health has deteriorated over the years. When given the opportunity to live in France, he refused because the documents did not name him as "Sir, Alfred", and he claims to have forgotten his native Persian language. Reportedly, he left the terminal in August 2006 to be hospitalized for an unspecified illness.
Nugget: a good film with a loveable performance by Tom Hanks, although you can pretty much learn everything you need to know about the film from the effective trailer.