France's Socialist government completed its nine-month nationalization battle today by naming managers for what is now the major example of state ownership among Western economies.

Competence rather than ideology, experience rather than new blood, continuity rather than surprise were the overall hallmarks of the predominantly establishment men and women named at the weekly Cabinet session to implement the controversial nationalization legislation.

In most cases the new managers were products of the elitist grandes ecoles, especially the National School of Administration and Polytechnics, which have fulfilled a similar function for the conservative governments that preceded Socialist Francois Mitterrand's presidential election victory last May.

The government's caution in choosing its new managers reflects the knowledge that, with their appointments, nationalization is finally operational and the real test of the Socialists' most controversial legislation is about to begin.

In two cases the old managers were kept on--Roger Fauroux at the healthy glass and construction giant Saint-Gobain and Jean Gandois at the ailing textile, chemical and pharmaceutical firm of Rhone-Poulenc.

Gandois had been criticized by the Communist-dominated General Confederation of Labor, and some analysts suggested that the Socialists retained him to signal that organized labor would not have its way automatically.

For the other three nationalized industrial groups the nod went to:

Jean-Pierre Brunet, a former career diplomat and one-time ambassador to Japan and West Germany, at the prosperous electronics and construction firm of Compagnie Generale d'Electricite.

Georges Besse, a tough-minded executive experienced in the nuclear field, at ailing Pechiney Ugine Kuhlman, a metals multinational.

Alain Gomez, a Harvard Business School graduate, left-wing Socialist and top Saint Gobain executive, at Thomson Brandt, an electronics and home appliance company.

At the two financial holding companies, Jean-Yves Haberer, the former director of the treasury who has served almost every conservative government for the better part of 20 years, became boss at Paribas. Georges Plescoff, a veteran financial expert and insurance executive, took over at the Compagnie de Suez.

Three women were among the top bank executives named. But the real surprises were outside the scope of the new nationalizations.

Communist Georges Valbon, a veteran Paris "Red Belt" politician with no technical expertise, was appointed head of the long-nationalized national coal company, and Michel Rolant, a leader of the pro-Socialist French Confederation of Democratic Workers, who has no more than a high-school education, was named to run the new energy-saving agency.

Speaking at the Cabinet session, Mitterrand indirectly rebutted his critics by telling his ministers that the newly nationalized banks and industries "must not become appendages of the civil service administration."

"Their autonomy of decision and action must be total," he added, in developing the government theme that nationalization was necessary to steer France out of the recession, unemployment and double-digit inflation.

After months of often heated debate and confrontation, the appointments announced today represent the end of the beginning for the nationalization process.

Opposed by the business community, attacked by the opposition in the National Assembly, originally rejected by the conservative-dominated Senate, thrown out and then accepted in amended form by the Constitutional Council, the nationalization law emerged from the nation's highest court with more generous compensation provisions for shareholders.

The cost of nationalizing five giant industrial concerns, two financial holding companies and 18 banks has been estimated at $7 billion, including the 25 percent increase that the Constitutional Council demanded last month. Most compensation will be in the form of government bonds to be paid off over more than a decade.

Although no official statistics have been published, some estimates suggest that along with the much smaller nationalizations in 1936 and just after World War II, the state now employs about 23 percent of industrial workers and exercises direct or indirect control over 3,500 enterprises representing as much as 32 percent of French industrial activity.

Although many foreign businessmen and potential investors have been worried by the industrial sector takeovers, their French counterparts appear more upset by the implications of the almost total government control of banking and credit.

The Socialists have made no secret of their desire to use the banks to encourage basic structural changes they consider necessary to make French industry competitive internationally.

At the same time, faced with more than 2 million unemployed, or about 9 percent of the work force, the government has also announced plans to reward with preferential loans those employers willing to take on new workers.

There has also been talk of using credit policy and the newly nationalized industrial firms, such as National Laboratories, to experiment with comanagement and worker self-management.

Employers have voiced concern about trade union suggestions that the nationalized industries should do more of their own subcontracting as a way of protecting their own jobs at the expense of small and medium-sized industries.

Despite some government statements that the new law does not mean guaranteeing jobs in the nationalized sector, the trade unions, pushed by the General Confederation of Labor, have served notice that they would not take kindly to layoffs.