It's a very familiar way to call someone named Francisco or whom we call Paco. It's similar to saying Paquito or Pachito. It was the stage name of a famous Spanish bullfighter named Francisco Rivera.
Francisco Rivera "Paquirri" was a Spanish bullfighter, well known for his career of almost 20 years of work and dedication. His death came from a bugle received on 26 September 1984.