Protesters shouted "the people want to overthrow the regime" and held up banners denouncing the government.
The prayer service ended with a demonstration filled with banners denouncing the United States and Israel.
The lead students, wearing gas masks and waving iron bars, held high banners denouncing the United States, which dissidents here say gave tacit consent to the bloody crushing of the pro-democracy movement in the southwestern city of Kwangju in 1980.
The marchers carried banners denouncing Mr. Le Pen and the National Front.
They tried to hang a banner denouncing energy development and to disrupt traffic with a disabled truck.
A few summers later, it hired a plane to fly along crowded beaches towing a banner denouncing a chemical company for plans to dump industrial waste at sea.
They carried banners denouncing the traffickers, praising the Government and waved white kerchiefs and strips of white paper.
Thousands of people will tie up the downtown area during a giant demonstration, and protesters will chain themselves to buildings or scale walls to unfurl banners denouncing the target of their ire: the World Trade Organization.
In another sign of the difficulties the government must confront, thousands of teachers and doctors protesting the planned budget and salary cuts marched on the presidential palace today, carrying banners denouncing the government's "submission" to the I.M.F. and the United States.
Scaling Sugar Loaf mountain, members of the Greenpeace movement draped Rio's landmark on Saturday with a large banner denouncing the Earth Summit for having "sold out" the planet.