The reform, proposed by the French government, envisions, in particular, abandoning the school-leaving qualification and tightening the criteria for entering a university.
The rally started around 10:45 GMT at the Place de la Sorbonne square in central Paris, which is traditionally used by students to hold demonstrations.
The protesters are holding posters with slogans: "Let Us Save Universities," "No to the Police State," and "We Are Unsatisfied."
Police and security forces are ensuring public order during the demonstration.
A major student demonstration took place in France in February with thousands protesting against the education reform across the country.