[Important note - 2019-01-07] If your translations don't work anymore after updating Easy Booking to version 2.2.0, you need to rename your .mo/.po files as follow (replace "fr_FR" by your own language code):
Compatibility with WPML (“Translation Management” and “WooCommerce Multilingual” addons required)
On the product admin page, find the “Multilingual content setup” metabox (usually at the bottom).
In there you should see have a “Custom fields translation” section. You need to find all the fields from Easy Booking in there, and set them as “Copy”.
The fileds are: