Raul Oliveira Neto, a 24-year-old visitor from the Southern Brazilian city of Porto Alegre, was one of the first to use the icon and thought the service fit well with the way people live now.
"We use so much technology to pass information, this makes sense," he said, noting he'd seen QR codes on tourist sites in Portugal, where they were first used for this purpose. "It's the way we do things nowadays."
Locals — used to giving visitors directions — also approved the novelty.
"Look, there's a little map; it even shows you where we are," said Diego Fortunato, 25, as he pulled up information.
"Rio doesn't always have information for those who don't know the city," he said. "It's something the city needs, that it's been lacking."