More than a million Catalans paraded in Barcelona on their "national day" today to press for immediate restoration of self-rule, which was abloished by the late dictator Francisco Franco following the 1936-39 civil war.

Participants in the biggest free political demonstration that Spain has witnessed in more than four decades were particularly jubilant because of strong indications that King Juan Carlos and Premier Adolfo Suarez appear prepared to grant the four Catalan provinces - Barcelona, Gerona, Lerida and Tarragona - a measure of autonomy soon.

The most dignificant sign that Catalonia, Spain's rich northeastern ethic region, is on the verge of recovering a portion of its lost home-rule and other regional rights, came late last night from Cifra, the governments news agency.

In a surprising dispatch that got wide play in the country's Sunday newspapers, the agency reported that the government and Catalan nationalist leaders had finally agreed on a formula for the provisional re-establishment of autonomy.

The agency also distributed the purported texts of three royal decrees on Catalan autonomy. They will go into effect, the agency said, once they are published in the official gazette.

Government officials could not be reached for comment, but Premier Suarez predicted that generalitat, as the former Catalon antonomous government was called, will be restored soon. During a recent vacation seaside resot. Suarez yat ch flew the "Seneyra," the Catalan flag that eas banned by Franco.

The premier has been negotiating with the exiled president of the Generalitat . Josep Tarradellas, 18. Tarradellas was in Madrid in July for talks with Suarez and the king and then returned to exiled in France.He has been coordinating talks for the restoration of Calatan self-rule with Catalan parlimentarians elected in last June's ballotting for Spain's first free representative legislature in 41 years many of whom are Socialists, Communists and nationalists. Autonomy was the left's man campaign slogan.

All indications are the king will appoint Tarradellas to hear a new provisional regional government is a strong nationalist but he does not oppose the monarch. The civil war president of the Generalitat. Lluys Company, was captured in France during World War 11, turned over to Franco authorities and executed by a firing squad after a brief trial for high treason.

Showing how things have charged since Franso's death, a message from Tarradellas was broadcast repeatedly throughout the day. He said that in a short time there will be a provisional "Generalitat" and that Catalonia is "on the eve of recovering a part - an important part - of our rights."

The king and the premier have been particularly lenient with Catalonia since Franco's death nearly 21 months ago. They appear to assume that by giving into Catalan demands they can provided a pattern for the restive and more violent Basque region, which is also pressing for the restoration of the autonomy it enjoyed under the republic that Franco defeated in the three-year conflict.

Franco considered autonomy for the Catalan and Basque regions one the republic's worst "sins," because he regarded self-rule as a threat to Spain's sacred unity."

Basque parliamentarians were in Barcelona, the spiritual home of Catalan nationalism for the celebration of the "Diada" as Catalan call there national holiday. Banned by Franco. Catalonia's day marks the loss of self-rule to the Bourbon monarch in 1714.

The region's four provinces, regained their autonomy with the flight of the king's grandfather. Alfonso X111, in 1931, and the advent of the republic. Almost fron the moment that he assumed the throne. Juan Carios began to make gesture toward Catalonia. He addressed them in their language during a visit, permitted the display of the Catalan flag and the publication of newspapers and magazines in Catalan.

This year's celebration - the first since 1939 in Barcelona - began last night. This morning, Barcelona was festooned with Catalan flags and posters of Catalan heroes and jammed with demonstrators carrying signs demanding autonomy, amnesty for all political prisoners, and legalization of all political parties that have not yet recognized by the government.

The atmosphere was festive. Hundreds of thousands of marchers sang the Catalan national hymn, "the reapers," and chanted, "We want the autonomy statue."

About 5,000 leftists gathered this morning at a Barcelona park where speakers assailed the monarch and demands "independence" rather than autonomy within the Spanish state.

Police kept away from demonstrators not only in Barcelona but in other Catalan cities. Nationalists changed the name plates of streets. resorting those used before the civil war and they placed wreaths at the feet of statues of Catalan heroes. Most of these monuments had been taken down by Franco in 1939, but replaced by nationalists in the past few months.