"We have gained nothing" in the three years since the movement began, said Andrea Gomez, a 43-year-old social worker who was among those gathered.
The protests came exactly three years after the start of a mass revolt against a rise in metro fares in 2019 that quickly escalated into a general clamor for better conditions and social equality.
The government suspended the price hike but protests continued, and dozens were killed over months of clashes. Hundreds of people were injured.
The demonstrations kickstarted reforms that included the government's agreement to the drafting of a new constitution to replace the one inherited from the military dictatorship of Augusto Pinochet and perceived as market-friendly.
Last December, Chile elected a leftist president in Gabriel Boric, who supported the constitution-writing process.
But last month, nearly two-thirds of voters rejected the proposed draft despite the new revolutionary mood, amid concerns that parts of the document were too far-reaching.
Boric, a former student leader who had supported the 2019 protests, on Tuesday called for a new social dialogue to give shape to much-needed social reform.
The 2019 uprising, he said, "was an expression of pain and fractures in our society that politics, of which we are a part, has failed to interpret or answer."
Boric came to office with promises of turning the deeply unequal country into a greener, more egalitarian "welfare state."
