Bonjour Rémi,
Thanks for joining us here on the Community. I understand it can be tricky to find an internship with such short notice and hopefully, my leads will help.
The French embassy in Ireland lists a few reliable links to look for an internship
on the island. In terms of hospitality and restaurant work, I found
this training page on the Restaurants Association of Ireland, which may be able to help.
I would also suggest contacting restaurants in cities (Cork, Galway, Dublin for instance), which may be open to hiring an intern. I would also try Irish cooking schools such as Ballymaloe Cookery School (Cork) or Dublin Cookery School for leads.
Best of luck and let us know if you need any tips to visit the island.
A bientôt,
Antoine