French Socialist leader Francois Mitterrand, head of the country's largest oppostion party, was charged today with violating the state telecommunications monopoly by making broadcasts over a private radio station.

Mitterrand, defeated by Valery Giscard d'Estaing in the 1974 presidential race, appeared today before an examining magistrate and was charged with having made tapes broadcast June 28 over a private Socialist Party radio station, Radio Riposte, in violation of the telecommunications law.

The Mitterrand broadcast, part of a Socialsist Party campaign to call attention to what it feels are the abuses of the state broadcasting monopoly, dealt with alleged misuse of police power, harsh court sentences meted out to young antigovernment demonstrators and growing unemployment in France.

French police intervened to halt the June 28 broadcast, beamed from Socialist Party headquarters in Paris, but failed to find the broadcasting equipment.

A second illegal broadcast was made July 30 from Socialist Party offices in the southern French city of Montpellier, and a third illegal program went on the air today from an unknown location. Today's transmission was organized by the Socialist Federation of the Normandy department of Calvados to coincide with Mitterrand's appearance before a Paris court.

Also charged with Mitterrand were Socialist Party spokesman Lurent Fabius and Sen. Bernard Parmentier. Both were present in the Paris party headquarters during the June 28 broadcast.

Mitterrand and the two other Socialists face prison sentences of from one month to one year, or fines equivalent to between $2,350 and $23,500.

Mitterrand, 62, said in a statement issued after his meeting with the examining magistrate that a "political trial" was being prepared against him.

The Socialist leader also said that the state monopoly on broadcasting was abused in France.

All three French channels are owned by the state, as are three domestic radio services. The state also has a majority holding in three commercial radio stations.

Opposition politicians frequently protest that French radio and television devote too much attention to government politicians, while denying the opposition equal time.

When the Justice Ministry announced after the Montpellier broadcast that Socialist members of parliament would be prosecuted, the Socialist Party described the move as "a derisory maneuver of diversion." The Socialists said they planned to continue the private broadcasts.