It is a warm April Sunday in the capital of the German Democratic Republic and blue-shirted members of the Free German Youth corps lounge in the parks waiting for the start of today's parade.

They will march to the Alexanderplatz, sing songs and hail the 10th congress of the Socialist Unity (Communist) Party, which began yesterday. Buildings are decked out with red flags and banners bearing slogans such as "Everything for the well-being of the people."

The blue-shirted youth lbrigades, the lingering smell of brown coal in the air, and the sight of bombed-out buildings still pockmarked with World War II bullet holes -- all are as they were seven lyears ago, the last time this reporter visited here.

If anything, the green-uniformed officers of the People's Police seem more fearsome. A visiting reporter applying his brakes sharply just in time to stop in front of a pedestrian crossing is waved over by a constable with a bulldog face.

"Get out!"

"Documents!" Press accreditation to the 10th Party Congress is quickly thrust forward, resulting in a slight moderation in the policman's demeanor.

"What you did there was not good." The policeman returns the papers, salutes, and the chastened driver slinks back to his car.

Journalists still have their problems here. A visitor calling an economics professor for an appointment is politely told that a new law requires Western journalists to clear all contacts with East German citizens with the Foreign Ministry.

Yet in this country, one almost has to reverse the old aphorism and conclude that "the more things stay the same, the more they change." First impressions are always misleading in East Germany, a country whose politics and internal realities are far more subtle and complex than they seem on the and internal realities are far more subtle and complex than they seem on the surface.

Even in the shadow of a political movement in Poland that threatens its own stability, East Germany seems more relaxed, more physically comfortable, more prosperous and more self-confident than seven years ago.

Many of the young people who marched in today's prade wore jeans along with their blue shirts and sported long hair as well -- a contrast to the rigid formality of such events only a few years ago.

The government nowadays even tolerates occasional impromptu blues and jazz concerts in local churches, often attended by overflow crowds of young people.

This more relaxed mood holds perils for the communist leadership, which plainly is determined to avoid the spread of the Polish Solidarity labor union movement. But even critics of the government's policies acknowledge that East Germans seem more reconciled to a life here and more aware of lthe country's statehood than they once were.

"If you took down the wall, 85 percent would go -- but 95 percent would return," said one worker.

Downtown East Berlin, an empty and sad place a decade ago, now seems more cheerful and bustles with activity.

At Checkpoint Charlie, the best known access point from West Berlin to East Berlin, one of the cars clearing through to the communist capital last week belonged to an East German family, one of the fortunate ones permitted to travel to the West.

West German television correspondents are now accredited to East Germany.

A new palatial abode, the Metropol Hotel, has been erected for visiting foreigners, but East Germans with foreign currency to spend also patronize the bars and restaurants.

Where religion is concerned, it is evident that the vision of Bertolt Brecht still takes precedence over that of Martin Luther. At a Palm Sunday service today in an old community church in the borough of Pankow, the handful of worshipers looked through the stained glass windows at red flags rippling in the wind from an adjacent building.

The pastor ascribed the small turnout to the fine weather.

But the Lutheran Church services with its position somewhat more secure than it was a decade ago. The communist government has included a new church -- the first to be built in the capital since the 1940s -- in plans for a new development.

Meanwhile agreements and treaties signed by the governments of the two German states have eased the hardship of families separated by the border between them.

These changes may not seem earthshaking, but they have made life better for the 17 million East Germans who live under unique political conditions.

As party leader Erich Honecker constantly reminds his compatriots, his ability to maneuver is restricted by the "realities" -- a code word understood by all East Germans to mean the country's geographical position abutting the North Atlantic Treaty Organization, the presence of 400,000 Soviet troops on its soil and the existence of the 857-mile, heavily fortified border that divides it from West Germany.

East Germany's cultural policies also are shaped by the need to respond to the strong pull exerted by West German television and radio, to which most East Germans have access. When a West German television correspondent here reported to his network that changes were expected soon in the operation of East German "Intershops" -- stores where Western goods are sold for foreign currency -- long lines appeared at the same shops early the next morning.

Compared with the press in the Soviet Union, Hungary, Poland and Czechoslovakia, television, newspapers and radio in East Germany play a smaller role in disseminating information. Instead, they spread the party line and give the government's position on events that many East Germans already know about -- a role that explains the media's uncompromising orthodoxy.

The communist leadership has taken the view that the "realities" leave little room for intellectual dissent.

After a period of mild liberalization in the early 1970s, controls were tightened beginning in 1976. The government has since banished a number of critics to West Germany and placed others under house arrest.

A 1979 report to the U.S. Congress on compliance with the Final Act of the Helsinki Conference on Security and Cooperation in Europe said that East Germany "invited" critics to leave the country and threatens to ban others from professional activities. Controls were tightened further in August 1979.

Sweeping amendments to the criminal code made passing information to Western journalists punishable by two to 12 years imprisonment. Some believe this was mainly meant to restrict West German television reporters, whose interviews here are seen by millions of East Germans.

Yet the Honecker government has been reluctant to resort to the harsh measures that have sent dozens of intellectuals to jail in Czechoslovakia and quelled dissent there. That is one of the ironies of current East German politics: disent is still officially sanctioned in a few carefully controlled settings.