Check a few replies here:

http://www.glocals.com/forums/geneva/where-how-in-geneva/Where-to-buy-second-hand-english-books-in-Geneva--130708.htm

these guys have book sales every so often.

http://www.amlib.ch/booksale.html

There will be a few thousand, mostly english,  at a Church sale at 57 rue de Montbrilliant (behind railway station) next Saturday June 21. 

Librairie

+41 22 311 10 90 *

There's a second hand book market on Place de la Fusterie every Tuesday and Friday, all day.

Hi... there will be Kermese at St. Nicolas de Flue Church at Montbrilliant this coming Saturday and there are a lot of English books for sale at a cheap prices... you may come and check it out

Where can I sell almost new English fiction books in Geneva ?

You could try the  Plainpalais market on Saturday mornings but best to inquire first before hauling a big pack of books that no one will accept .

The book market is way down and you won’t get much (if anything) for your trouble.

To give books away for free, you can contact Caritas, the Centre Social Protestant and the English-speaking churches in and around Geneva and Lausanne.

There’s an enormous need and demand for English books in Africa and elsewhere but sending or taking them to individual countries can mean that the recipient(s) will have to pay customs duty at the port of entry without any guarantee that the consignment won’t go walk-about between the arrival point and the true destination.

It’s so sad that so much worthwhile and needed literature is going to waste.

Ritchie

You could list them on Glocals.

There is an English library in Geneva http://thelibrary.ch/

They will organize the next book sales event on 10th of November, check the details http://thelibrary.ch/eventsactivities/book-sales/