You export your products and you get an error message like this one:

Incorrect Code EAN for the products, Products Identifiers:  [2/7, 2/8, 2/9, 2/10, 2/11, 2/12, 3/13, 3/14, 3/15, 4/16, 4/17, 4/18, 4/43, 4/44, 4/45, 5/19, 5/20, 5/21, 7/37, 7/38, 7/39, 8/47, 8/48, 8/49, 8/50, 8/51]

It is a list of product and combination identifiers, in the format 1/2, 1 is the product ID, and 2 the combination one.

Each product contains an EAN whose verification key is incorrect, that means that the EAN code does not match the GS1 specifications or has not been issued by GS1.

Marketplaces require that EAN codes are only issued by the GS1 organization, the codes generated by other modules or software, lists that are sold or available for free on the Internet do not allow the export marketplaces.

Visit our blog about this subject :
http://blog.common-services.com/prestashop-codes-ean-places-marche/