Good afternoon Laurent and welcome to the Events Calendar forum!
Thank you for your interest in our products.
We’ll be glad to answer your question.
When I test Event Calendar, on the french version. The links to /events/mois/ (months traduction) or /events/liste/ (list traduction) returns 404 errors, but the english links work.
Actually, this is typically because you need to re-save your permalinks after changing the language.
I just tested it out in French and it works perfectly.
Let me know how that goes.
Best regards,
Geoff B.