Organized by a student group, #Yosoy 132, protesters aimed to surround the network offices for a 24 hour period, blocking entrances to network personnel during Televisa's broadcast of the blockbuster Olympics inauguration.
The building was protected by a large police presence.
The protesters accuse Televisa, the world's largest Spanish-language television network, of tilting election coverage toward the winner of Mexico's July 1 presidential election, the PRI's Enrique Pena Nieto.
Protesters chanted "Mexico without PRI" and read a manifesto demanding the "democratization of the ownership of all communications media."
Pena Nieto's victory, challenged by leftist candidate Andres Manuel Lopez Obrador, marked the return to power of the Institutional Revolutionary Party, which ruled Mexico for most of the 20th century until its ouster in 2000.