I also can say Chania is very nice place. It has old venetian architecture and during the winter is very cheap.
By the way A3 also offers very cheap prices when flying xxx-ATH-CDG or xxx-ATH-IST (or vice versa for IST). For example sometimes you can fing SOF-ATH-CDG or even IST-ATH-CDG with airfare just 9 EUR + 33 EUR taxes on their website so it could be even cheaper bought from somewhere else.