Here's the comment with a better explanation of the video and aftermath, I edited it for typos and clarity:
"If anyone wants the story and how it ends : This guy, who actually harassed the homeless guy before, belongs to the SPA (French PETA). He and his stupid friends decided that the dog was unhappy and underfed so they stole it (as seen in the video) and put him in a shelter and tried to put the pup up for adoption for 175€. (I think I've heard the poor puppy refused to eat and cried often in the shelter, but I'm not sure).
Anyway, as the blond woman said in the video : this is illegal in France, because it is theft. Associations for the homeless rushed to the homeless man's help and he got his puppy back! Police arrested the man in white on the video and forced him to give the dog back.
Edit : the video is confusing but the blond woman tries to stop the guy in white, she is the one who calls the police."