I saw Yelle a few months ago in DC and 9:30 club and *loved* their performance. They sing exclusively in French and draw a very large crowd. I only expected a handful of people to attend but the show sold out in DC with people asking for extra tickets outside. I plan to attend and hope you listen to their music on youtube and go with me. I recommend such tracks as: J'ai Bu or Unillusion. That will give you a flavor.