The protest was organised by a group calling itself the "Unsustainable Olympics Committee" and demonstrators in the crowd held painted signs reading "Fake Snow Real Profit".
The Games will be held in two main locations - Milan itself and the Alpine ski resort of Cortina D'Ampezzo, and the protesters said that a large area would suffer damage because of the construction work needed.
Warmer winters in Italy are also making it more difficult to guarantee snow cover without resorting to cannons to produce an artificial variety.
Economy Minister Giancarlo Giorgetti said last week that he was increasingly worried about delays in preparations for the Olympics that will run from February 6th-22nd in 2026.
The Italian authorities have just signed a deal with a construction firm to build a sliding track in Cortina, aiming to resolve a long-running area of delay and uncertainty.
