Hello, @amandine,
1. I have just checked your site and found that you did not translate the theme in any language: https://postimg.cc/fJTVb906 you have to translate the theme in your desired language and then it will work for you, you can refer to the theme doc that I shared with you in my last reply.
2. And for the text white issue, please copy and paste the below-given CSS code to XStore >> Theme Settings >> Theme Custom CSS >> Global CSS and check back to your site after removing the browser cache.
.message .message__container.locale--FR .message__content .message__messaging span.tag--default span.br {
color: #fff !important;
}
Regards 8Themes Team.