Behaved like an ass when drinking in Paris, and got cheated (8)
I believe the answer is:
betrayed
But I can't explain it at all! Could you help me understand?
(Other definitions for betrayed that I've seen before include "Was unfaithful" , "Was disloyal to (someone)" , "Was disloyal, assisted enemy" , "Denounced" , "Delivered to an enemy by treachery" .)