It is true that I have no experience at all with putting accurate numbers to crowds. As a filmmaker I do have keen eye however and what I noticed were the numerous side roads which were also packed full of people yet the cameraman chose not to go down them. My point is that we didn't even see the full scale of this protest. The only way of course would be looking down from the air. With a lovely high resolution photo ideally. If only I had been there with my drone this is what I would have provided for you! Alas, we make do with what we have and make estimates the best we can. That being said, 100,000 across the whole of france is a joke to me. Not a chance.