Bonjour Timothé,
It's great that you are coming to Cork for a semester!
Accommodation in big cities can be challenging to find, but hopefully you'll end up finding what you need!
I usually recommend housing platforms such as daft.ie or myhome.ie. In Cork, I found student residences to offer rooms for an entire year, but you could check out sites such as
Rent Your Nest for instance. You can also look at international students or expatriates Facebook groups who may be able to give you leads on subletting or shorter leases.
Here is also
a past thread from a student looking for accommodation that might help you.
Best of luck, and let us know if you'd like tips to explore County Cork and beyond during your time with us.
Antoine