Language management problem

Hi OS solution team,

I'm finding some troubles to manage my events registration in multiple languages.

The default language of my Joomla! site is set to french.
So I have 2 site languages installed: english and french.

I've created 2 menu links:
- 1 link to my event detail with language set to french
- 1 link to the same event detail but with language set to english
The language association between these 2 links is created so that I can play with the Joomla! language switcher.

When switching language, all the translated strings managed per event or per field through the Translation tab of the create/edit panel, are well rendered.

But the translated strings managed with the main translation tool (/administrator/index.php?option=com_eventbooking&view=language) are not correctly changed. Everything is still displayed in english.
For example when displaying the site in french the event booking buttons are diplayed in english so are the general titles ("Individual registration", "Properties", "Payment information"…)

My configuration:
Joomla! 3.4.8
Eventbooking 2.2.1
PHP 5.5.30
MySQL 5.1.31

Thank you for your help
Simon

Edit:
I've attached a screnshot of my french registration form with debug and debug kanguage enable