This activity--some of it quite aggressive--is intended to express the urgency with which people regard the climate talks to take place among world leaders.
I hope these world leaders are listening, and persuaded that the people demand significant climate action. A healthy planet is a very popular idea to the people living on it!
Update--from Democracy Now! a video I hope is not symbolic:
VIDEO: Paris police vans run over shoes set out by activists as symbols of canceled #ClimateMarch. #COP21 pic.twitter.com/h0iM5utBWj— Democracy Now! (@democracynow) November 29, 2015