It's a first lady faux pas -- wearing expensive, high-fashion French designer sneakers to a food bank. Michelle Obama wore the sneakers, made by Lanvin, while helping feed the poor at a Washington food bank on Wednesday. The pricetag on the footwear? A cool $540. Keds, they're not. The sneakers, which come in denim and satin, are a favorite of comic Ellen DeGeneres and rapper Kanye West -- and they're "certainly not a reflection of the poor economy," said FOX News' Noelle Watters, host of iMag Style. "She paired the kicks with a much more reasonably priced cardigan from J....