The walls Rosembert tags show images of children with Santa Claus and a snowman, and a young wheelchair-bound child thrusting a bleeding Haitian flag into the air.
"I like to help everbody to pay more attention with God," Rosembert said, "because if we get more attention with God, then things will not get worse."
Rosembert had been tagging walls for a few years when the massive earthquake leveled parts of Haiti one year ago. He raced to make sure his family was safe and then set out shortly after to change his graffiti messages.
"I'm just doing this to help and to help the young and everybody to change their mind to get positive," he said.
And in a city like Port-au-Prince, where most people cannot read and write, his graffiti, he said, is understood by everyone.
"I just want," he said, "to make a difference."