Don't let me dissuade you from buying books. None of Rick's books cover Genoa proper or Palma de Mallorca.
Clearly you still need something for Paris and I'd choose one of the dedicated Paris books over the small bit of extra Mediterranean coverage that might be in the big France book (and which is still less than the Provence/Riviera book, but you won't have much time there).
The dedicated Paris, Barcelona, and Rome city guides include more self-guided walking tour and museum routes, but you can also see some of those in Rick's free Audio Tours or App. They have more on the topic of dining styles (or will you be back onboard the ship for dinners?) and on city history (e.g., "Three Millenia in Eight Pages" for Rome).
The Rome chapter of the general Italy book is about 50 pages longer than the chapter in the Cruise book, but a dozen of those pages are additional hotels and others may address sites that you don't have time to get to on a cruise stop, airport info, etc. [edited] Additional possibilities that are covered in the Italy book include the Cinque Terre (about 2 hours from Livorno, versus Florence is closer to 1.5 hours), and north of there around S. Margherita Ligure and Portofino. Some cruise ships now stop even closer in La Spezia, which is bringing a lot of cruise-traveler-traffic to the Cinque Terre.
If you'd like more fun with languages, consider the related phrase books.
