The march commemorating one year of the disappearance of the 43 students of Ayotzinapa left the official residence of Los Pinos and is heading to the Zócalo.
The Ministry of Public Security of Mexico City (SSPDF) reported that Paseo de la Reforma avenue is closed due to the demonstration.
Although the Government of Mexico City (GDF) said that there would be no riot police presence, several streets near Paseo de la Reforma avenue are guarded by the officers.
Several vehicles of the Human Rights Commission of Mexico City (CDHDF) joined the march to ensure that it takes place peacefully and without police abuses.
According to Mexico's former attorney general, the 43 disappeared in an attack by police and the Guerreros Unidos drug gang because they were mistaken for rival gang members. The attorney general said last November they were killed and burned to ash in a giant pyre in the nearby Cocula garbage dump.
The independent experts assembled by the Inter-American Commission on Human Rights took apart that version earlier this month, saying authorities knew who the students were from the minute they headed for Iguala, and at the very least did nothing to stop the attacks.