Following the execution of Louis XVI and the suppression of the Catholic Church their respective art collections became property of the French people, as did many works of art confiscated from émigrés (those who had fled the country as the Revolution progressed). The public could view the initial collection of 537 paintings and 184 other works of art for free on three days a week. The French government pledged to provide 100,000 livres per year to expand the collection, but the military successes of the Republic resulted in many works of art from across Europe being brought back to France – a process that continued during Napoleon’s reign.
If you wish to learn more, visit the history pages on the Louvre web site.