Star Wars Ambush At Corellia Book One of The Corellian Trilogy by Roger Macbride Allen

A trade summit on Corellia brings Han Solo back  to the home world he left many years before.  Arriving on the distant planet with Leia, their children  and Chewbacca, Han finds Corellia overrun with  agents of the New Republic Intelligence and finds  himself part of a deceptive plan whose aim not even  he understands. One thing is clear: the five  inhabited worlds of the sector are on the brink of civil  war and the once peaceful coexistence of the three  leading races -- human, Selonian, and Drallan --  has come to an end.