After a stalemate in the first half, goals from Alexis Vega, Sebastian Cordova, Uriel Antuna, and Eduardo Aguirre gave the Mexicans the perfect start to their Olympic journey.
France, without many of its biggest stars after their participation in Euro 2020, did find a goal through Andre-Pierre Gignac but must now pick themselves up after a humiliating defeat in Group A's opening game.
Meanwhile in Group C, Spain was held to a goalless draw by Egypt despite boasting an array of attacking talent.
Unlike many teams at this year's Olympics, Spain has included members of the Euro 2020 squad that reached the semifinals of the competition. Among them is teenage sensation Pedri as well as RB Leipzig star Dani Olmo.
However, it couldn't find a way past a resolute Egyptian defense.
Elsewhere, New Zealand beat South Korea 1-0 to take the early lead in Group B and Ivory Coast beat Saudi Arabia 2-1 in Group D.