The mayor of Brazil's biggest city has signed a decree authorizing the use of smartphone-based ride-sharing-applications like Uber.

The decree signed Tuesday by Sao Paulo Mayor Fernando Haddad says Uber and other companies offering the same kind of service must pay the equivalent of $0.03 cents per kilometer ridden with a passenger.

The service has drawn increasing use since soccer's 2014 World Cup, with many of its cars cleaner and newer than those of regular taxis.

Cab drivers protested in front of City Hall and blocked several streets and avenues. They complain Uber is unfair competition because its drivers don't have to pay city fees or undergo official inspections.

Uber's Sao Paulo office did not respond to an emailed request for comment.