The restaurant in Liberty City was named after a character Rockstar barely used.

Marco's Bistro in GTA III and Vice City is named after Marco Forelli, yet he appears in only one cutscene with almost no dialogue — making the eponymous restaurant more memorable than the character himself. He later became Forelli Family don after Sonny's death, only to be assassinated himself in 1992.

Source: Marco Forelli — CC BY-SA