How to manually install translations files on WooCommerce 2.2+?

Question

I want the WooCommerce plugin to display french text (fr_FR). The rest of Wordpress is correctly set to french but WooCommerce still shows english.

Since version 2.2 language packs are not included. This message is displayed on the admin page:

The recommended automatic "Update translation" procedure involves giving FTP access to my server which I would like to avoid.

There are fr_FR translations available in the WooCommerce git repo:

https://github.com/woothemes/woocommerce-language-packs/raw/master/packages/fr_FR.zip

I've unziped that in the same folder as the default english language files.

$ ls -l wp-content/plugins/woocommerce/i18n/languages 
total 1320
-rw-r--r-- 1 knarf users 211452 24 sept. 18:01 fr_FR.zip
-rw-r--r-- 1 knarf users 116765 22 sept. 10:48 woocommerce-admin-fr_FR.mo
-rw-r--r-- 1 knarf users 211901 22 sept. 10:48 woocommerce-admin-fr_FR.po
-rw-r--r-- 1 knarf users 162575 18 sept. 14:48 woocommerce-admin.pot
-rw-r--r-- 1 knarf users 163575 22 sept. 10:48 woocommerce-fr_FR.mo
-rw-r--r-- 1 knarf users 268719 22 sept. 10:48 woocommerce-fr_FR.po
-rw-r--r-- 1 knarf users 208795 18 sept. 14:48 woocommerce.pot

I've tried setting WPLANG to french in wp-config.php:

define ('WPLANG', 'fr_FR');

Despite all this, The "WooCommerce Translation Available" message is still there and WooCommerce interface is still in english. How do I force WooCommerce to switch to french?

Running the "Force Update Translation" procedure (from the message) fails with:

Failed to install/update the translation: An authentication error occurred while updating the translation. Please try again or configure your Upgrade Constants.

I'm using a fresh install of WordPress 4.0 (french release) and WooCommerce 2.2.4.

Answer 1

From the Translation Docs

PO and MO files will be downloaded in wp-content/languages/woocommerce.

So the woocommerce plugin folder is the wrong place to upload the language pack.

Edit: Important note concerning Language codes

Per @Julian Moreno's comment, the language code (and subsequent code) for WooCommerce must match the code you are using for WordPress.

In my case WordPress is "es_MX" and WooCommerce must be also "es_MX".