"If the Hitler salute is displayed on our streets today, it is shameful for our country. Politicians must do our part, but it is a challenge for the whole of society: we have to take a stand against the far-Right."
Maas said Germans had to speak up for basic rights. "My generation has been given freedom, the rule of law and democracy. We didn't have to fight for it, and sometimes we take it for granted. We have to get up off the sofa and open our mouths."
Protests at Chemnitz lasting several days came after the death of a German-Cuban man in a suspected stabbing by two migrants from Iraq and Syria.
More protests passed off largely peacefully on Sunday amid a heavy police presence. Eighteen people suffered injuries in scuffles, but none was seriously hurt.
More than 11,000 people took part in the rival rallies, according to police. Protesters poured into Chemnitz from across Germany.
The nationalist Alternative for Germany party (AfD), which has seen its support rise in the polls since the protests began, held a silent march through the city led by Björn Höcke, one of its most controversial politicians, who has previously called for a "180-degree turn" in German attitudes to World War II. The AfD march joined a demonstration by the anti-Muslim Pegida movement. Left-wing "Antifa" protesters held a rival rally, and police were deployed to keep them apart.