You both are correct but to me that is what makes it an unrealistic scenario. Most if not all real mobsters are sociopaths and don't give a damn what people outside the life think of them. Inside the life they want respect and they have to earn it through fear. It's just my opinion but in a real life situation friendship or no friendship Tony would have taken the restaurant or at least a portion of it. It would also be more profitable to take the restaurant than try to collect from the French guy who has nothing of value to Tony.