The Frenchman you are referring to is a global quack. His "investigation" was conducted over the internet by looking at photos he was able to Google.
A plane hit the building. Hundreds of people saw it. People who were actually there, not in France or on the internet.
The people who boarded that plane died in the crash. They are not living on some island somewhere. They died when their plane hit the pentagon.
You know that, and I know that, but apparently the Iranian Nutjob does not. Strange world we live in.