The streets are barricaded for this occasion. You just can't be a normal Parisian a few hours before the parade. The barricades prevent you from crossing over the avenue when you desire, not caring about the traffic. Moreover, the tourists have descended into the city. The tourists and the locals throng over the barricades making it impossible to get a good shot. The difficulty of this can be explained with just one picture; the man standing on the bicycle to watch the parade.
My meticulous friend brought a foldable stand for elevation. But he encountered an unforeseen hurdle. The security personnel had divided the sidewalks into two halves. One half close to the avenue is for people to watch the parade and the other half for normal traffic of pedestrians. When you wanted to switch from pedestrian to the one who watches the parade, you had to undergo a security check. Some security personnel allowed you to take the foldable stand with you while others did not!
The net effect was I could only picture the fighter planes which signaled the start of the parade. Enjoy the pictures.