One thing I really love is something I like to call dressy sweatpants. I know what you're going to say, that sounds like an oxymoron and it is but that's what's so great about them. Pair them with a chic little jacket and a pair of great shoes with a small heel and you can rock sweat pants all day long! I seen many a chic french woman doing just this.
I like these Vince pants from Shopbop. They have just enough tailoring to accomplish the effortless look I'm describing.