Indian arrogance is indeed amusing, i guess time will tell whether the Marines and the Ambassador walks scot free. So far, all the analysts and experts are predicting that the Ambassador will not be prosecuted and i agree with that conclusion. Also, time will tell which side the French will support. So far it seems that the Italians have secured the consent of the EU, the French have at no point stated that they will support India in this case so your entire hypothetical scenario is pretty much garbage. It will certainly be a real bruise on the Indian arrogance if the Italian Ambassador walks free without any consequences.
This is the point I was making earlier, the sheer arrogance of Indians is truly amazing and pathetic to say the least.
The mere fact that the incident happened in International waterskiing was initially disputed and then admitted and the fact that the Italians, despite this fact respected India as a nation and surrendered its marines, who being on board foreign vessel could easily have called for support and escaped, nonetheless they were humble and surrendered themselves in order to diplomatically deal with the matter at hand. Yet, despite the lie told by India that it had happened in local waters and then accepting the blood money for its two citizens killed, they still put themselves in a stupid position and went for trial. They should have at least sat back and looked at their jurisdiction in the first place.
The marines should not have been there in the first place and it is clearly the Italians made this move as a last option after a lack of meaningful dialogue and outcome from the Indian judiciary who itself is showing its clout.
Looks as though the Italians can raise this now in the International forum and let's see where this case goes in a neutral trial, I say it will last half a day