"人民" is political word, and try to express some positive impression (for the government) of people, . "民众" is neutral, sometimes negative. You can see in Chinese news, if they call some people "人民", they will usually say how good they are , or they are doing something right. And if they call some people "民众", normally they will say they are doing something not so good(e.g. fighting). The world "人民” is abusing, or just like a political slogan. Actually, we don't know who belongs to "人民" in China. But I know most of the people are "屁民“

中华文化博大精深~

我比较赞成第一个回答。人民和民众。这两个词是带有政治意味的，在一个国家，你支持的是执政党的，你就是执政党的人民，同时也是民众，不支持的就是民众。民众的范围更大，人民包含在民众里面。

tiens, je vous donne un dictionnaire en ligne: www.frdic.com

人民：百姓；平民。指作为社会基本成员主体的劳动群众；也指一个国家的普通人，区别于少数有特权者；也泛指人类。/ means the people 民众：泛指人民大众；也指人民众多。/ the masses of the people; the common people; the populace