Uber, the San Francisco-headquartered mobile ride-hailing service, offers rides from 15-29 euros (USD 17-34) from Madrid's airport to the city center. The fare for taxis is set at 30 euros (USD 35).
In a statement yesterday evening, Madrid's city hall says "(Uber's) tariffs may violate several articles of the Law of Unfair Competition and consumer rights if they are below the cost of providing the service."
Taxi drivers in Spain went on strike in March and May to protest what they say is unfair competition from Uber and the Madrid-based car service Cabify.