Good evening Dorian and welcome back!
Thank you for reaching out to us.
I would love to help you with this topic.
Also, if you prefer, we can absolutely continue this conversation in French.
Technically, we do not officially support Qtranslate usage with our plugins.
We are gradually making all of them compatible with WPML for multilingual sites instead.
With that in mind, you can edit many things in our calendar.
You might want to read our Themer’s guide to get a sense of how that works.
It even points you to the files to edit to do a template customization of the emails that get sent.
Let me know if that helps.
Have a great day!
Geoff B.