Unless the color is just washable with simple water , I would send to Greenpeace France the bill to clean it up and repaint it.
But since there is a breach of security and that CDG is protected by the Gendarmerie, I am pretty sure they will be eager to look for and find who organized this and who was on the video . they will not only be charged with vandalism but with security breach , a far more serious offence for the Gendarmerie .