CAT Return

You only need to file once 80% of the threshold has been met, so if you're getting any amount under €268k you do not need to file

You only need to file it when it's above 80% of the threshold, so if she's giving you €100k you don't have file it. However it's based on gifts received from that group since 1991, so say she gave you €200k five years ago, and €100k today, then you've exceeded 80% of the threshold and would be required to file it.

Don't forget your Mother and Father can each gift you €3000 every year tax free. This would be separate to the €355K allowance