Libbyliblib: The thing is, there is likely an exclusivity clause in Klavan's contract with the publisher, so that Klavan can't shop the book around to another (French) publishing house for a certain period of time. Thus, Klavan loses out on royalties for the unpublished book and also getting his book read. (And writing is notoriously not an industry you go into for the money.)

Additionally, since Klavan writes that the publisher is in breach of their contract, why not take him at his word that there is something in his contract that guarantees that the publisher, er, publish the book? Probably, the end state will be that Klavan gets to shop his book around to other publishers. But he may have to go through legal hoops to get the exclusivity canceled, which eats up time and money.