OK. Even though this comes within the scope of CAT I dont believe there would be a liability on this sum. For the following reasons:
CAT is gift tax. The gift in this instance is not the €80,000 but the lend or free use of the €80,000 interest free. So the actual gift is the amount of interest that could be earned if it was on deposit. So assuming the full €80,000 was given up front and assuming a 5% interest rate then the benefit would be worth €4,000. You have a small gift exemption of €3000 which leaves a taxable value of €1,000. On top of this you have a CAT group threshold of €20,740 for 2010 for a gift from a friend. The group threshold means that you wont pay CAT on a gift from a friend until all their gifts combined exceed the threshold and this will not happen in the case of an €80,000 loan over 5 years as described above. hope this helps