First, said Rs. 1.5 is still payable or become an income for your client?
If same is become an income, one needs to see if same is in penal character or falls under the term "agreeing to the obligation to refrain from an act, or to tolerate an act or a situation, or to do an act''. As lot of these issues can be decided only after studying the facts involved, underlying agreement/s, terms of settlement etc., it is best to consult an expert.
These are ex facie views of mine and the same should not be construed as professional advice / suggestion.